statistical computation of tolerance limits

48
NASA Technical Memorandum NASA TM- 108424 CsP (NASA-TM-10842_) STATISTICAL COMPUTATION OF TOLERANCE LIMITS (NASA) 45 p N94-15535 Unclas G3/65 0190807 STATISTICAL COMPUTATION OF TOLERANCE LIMITS By J.T. Wheeler Structures and Dynamics Laboratory Science and Engineering Directorate October 1993 NASA National Aeronautics and Space Administration George C. Marshall Space Flight Center MSFC - Form 3190 (Rev. May 1983)

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Page 1: Statistical Computation of Tolerance Limits

NASATechnicalMemorandum

NASA TM- 108424

CsP

(NASA-TM-10842_) STATISTICALCOMPUTATION OF TOLERANCE LIMITS

(NASA) 45 p

N94-15535

Unclas

G3/65 0190807

STATISTICAL COMPUTATION OF TOLERANCE LIMITS

By J.T. Wheeler

Structures and Dynamics Laboratory

Science and Engineering Directorate

October 1993

NASANational Aeronautics and

Space Administration

George C. Marshall Space Flight Center

MSFC - Form 3190 (Rev. May 1983)

Page 2: Statistical Computation of Tolerance Limits
Page 3: Statistical Computation of Tolerance Limits

TABLE OF CONTENTS

INTRODUCTION .........................................................................................................................

MATHEMATICAL PROCEDURES ............................................................................................

One-Sided Tolerance Limits ...............................................................................................

Method A ...............................................................................................................

Method B (New Theory) .......................................................................................Two-Sided Tolerance Limits .............................................................................................

Method A ...............................................................................................................

Method B (New Theory) ........................................................................................

NUMERICAL RESULTS .............................................................................................................

NONPARAMETRIC TOLERANCE LIMITS ..............................................................................

CONCLUSIONS ...........................................................................................................................

APPENDIX A: Derivation of Chi Distribution .............................................................................

APPENDIX B 1: One-Sided Kp ....................................................................................................

B2: Two-Sided Kp ....................................................................................................

APPENDIX CI: Simulation Code for One-Sided k .....................................................................

C2: Simulation Code for Two-Sided k .....................................................................

REFERENCES ...........................................................................................................................

Page

1

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4

4

6

7

7

8

10

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30

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32

33

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111

pRF.CE!)_IG PAGE BLANK NOT FILMED

Page 4: Statistical Computation of Tolerance Limits

Figure

1.

2.

3.

LIST OF ILLUSTRATIONS

Title

Normal distributions for one- and two-sided tolerance limits .....................................

Area of integration for one-sided tolerance limits .......................................................

Area of integration for two-sided lower limits .............................................................

Page

3

6

8

L

w

ivL

Page 5: Statistical Computation of Tolerance Limits

LIST OF TABLES

Table

1.

2,

.

.

.

,

,

,

.

12.

Title

One-sided k; Pr(T v <_k I'_ I Kp l'g) = 7' ;

One-sided k; Pr(Tv <-k l'_l Kp l'ff) = 7';

One-sided k; Pr(Tv <- k :ff l Kp l-if) = 7';

One-sided k; Pr(Tv <- k l'ff l Kp g'if) = 7";

One-sided k; Pr(T v <_k l-ff I Kp l'if) = 7";

Two-sided k; Pr(T v _k 1-ff I Kp gh') = 7';

Two-sided k; Pr(T v <_k l'_ l Kp g-if) = 7";

Two-sided k; Pr(T v <_k ,/'dik e g'_) = 7';

Two-sided k; Pr(T v < k ,/-ff IKp g-if) = 7";

Two-sided k; Pr(Tv <-k l'_ l Kp g'if) = 7';

7' = 0.50 .....................................................

7' = 0.75 .....................................................

7' = 0.90 .....................................................

y = 0.95 .....................................................

7'- 0.99 .....................................................

7' = 0.50 .....................................................

7' = 0.75 .....................................................

7'= 0.90 .....................................................

7'= 0.95 .....................................................

7' = 0.99 .....................................................

Comparison of approximate and exact results for two-sided tolerance factor kfor n = 2 and 10 .........................................................................................................

Nonparametric tolerance limits ...................................................................................

Page

12

14

16

18

18

19

21

23

25

25

26

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Page 6: Statistical Computation of Tolerance Limits
Page 7: Statistical Computation of Tolerance Limits

TECHNICAL MEMORANDUM

STATISTICAL COMPUTATION OF TOLERANCE LIMITS

INTRODUCTION

The need for improved, accurate computation of tolerance factors is accomplished by a new

theory associated with the numerical integration of the equations to yield exact solutions. The computer

codes have been developed specifically to integrate the equations of some statistical properties for a

normal (or Gaussian) distribution by application to the particular one- and two-sided tolerance limits.

For the normal variate X with known mean # and known standard deviation o', a specified pro-

portion of the normal population (1) is contained above the lower tolerance limit, L = p-Kp o', or below

the upper tolerance limit, L = I.t+Kpcr, for the one-sided case, and (2) falls within the lower and upper

tolerance limits for the two-sided case. Kp is the deviate corresponding to the proportion for the inverse

normal probability distribution.

However, in most situations, the mean p and standard deviation o"frequently are unknown.

Therefore, the objective of the tolerance-limit analysis is to obtain the numerical solutions to the prob-

lems involving the probability distribution for the sampled population with the normal distribution with

unknown mean p and unknown standard deviation o'. Furthermore, it results in the calculation of the

tolerance limits based on the mean x and the standard deviation s of the random sample. Thus, by the

statistical theory, the tolerance limits can be calculated out by the following equations:

L = F-ks

U = X+ks,

(1)

where x is an estimate of/.t and s is an estimate of ¢rof the normal distribution computed from a sample

of size n. The quantity k is the tolerance factor. Since x and s are considered random variables, the toler-

ance limit statement is applied to the given probability. Now, to ensure stability of the numerical solu-

tions, it is necessary to determine k such that the probability is 7, that at least a proportion p of the popu-

lation is above F-ks or below X+ks for the one-sided case and lying between the limits for the two-sided

case.

The statistical tolerance interval :_+ks covers the prespecified proportion p of the sampled distri-

bution with 100 ypercent confidence for the cases where a sample x!, x2, x3 ..... xn represents the random

sample from the normal distribution with mean p and standard deviation 0". The ordinary statistical

methods assume the following equations:

X ± _ xi, (2)--tl i= 1

as a sample mean and

Page 8: Statistical Computation of Tolerance Limits

s=_/nl_-l_(Xi-_}2i= ' (3)

as a sample standard deviation.

In the one- and two-sided cases, tolerance limits can be derived using noncentral t-distribution.

Mathematically, the problem is to find k such that

Pr{Pr(X<_._+ks) > p} = 7, (4)

where X has the normal distribution with mean/1 and standard deviation o'. 7is specified probability.

Some tables for the tolerance factor k have been generated using inputs of sample size n, proportion, andprobability. The values of k pertain to percentage points of the noncentral t-distribution. Specifically,

Pr{noncentral t _<k/-gl g = Kp,/-ff} = y, (5)

where the noncentral t-distribution has v degrees of freedom.

Normal distributions for one- and two-sided tolerance limits are depicted in figure 1.

Wald and Wolfowitz, in their technical paper, had developed an approximate formula, which

shows that k is approximated by

k = ru, (6)

where r is determined from the normal distribution by

.(1 + r)__(1- r), (7)

with

and u is defined by

• (t)=_ **ex --_- dz,

v (8)u= Z v) '

where Z _v) is the upper 10Og, percentage point of the chi-square distribution with v= n-1 degrees of

freedom. For v = n-l, the approximation converges to the true limits as n approaches infinity.

2

Page 9: Statistical Computation of Tolerance Limits

i'÷ksOne-sidedtolerancelimits

Theprobability is (1-o0 thatat least100p percent of the population lies below (or above)the tolerance limit F = _e+k _s (or F -- :g-k :).

Two-sided tolerance limits

is(1- _)that at least 100 p percent of the population is containedThe probability

between the tolerance limits F_ = :r+k2s and F2 = 7t-k2s.

Figure 1. Normal distributions for one- and two-sided tolerance limits.

3

Page 10: Statistical Computation of Tolerance Limits

MATHEMATICAL PROCEDURES

The mathematical procedures are given for determination of exact tolerance limits for the one-

and two-sided cases.

One-Sided Tolerance Limits

Method A

For the noncentral t-distribution, let w denote a random variable having a normal distribution

with mean zero and variance one; let v denote a random variable that has a chi-square distribution with v

degrees of freedom; let the quantity 6 be any constant; and let w and v be stochastically independent.

Then T(fi) = (w+_)/_ has a noncentral t-distribution with noncentrality parameter 8 and v degrees of

freedom.

Thus, a standardized normal variate is given

W 2

1 ---U

g(w) = _ e ,-_,<w<_ (9)

and an independent chi-square variate based on v degrees of freedom is

V

h(v) = 1 (_'_) -_v v e 0<v<o* (10)

Then the joint distribution ofw and v is the product of equations (9) and (10):

Q(w,v) = g(w)h(v) ,

1Q(w,v) =e . 1 v v e -_ . (11)

The new random variables are introduced, namely,

t= w+S u = ,17 . (12)

Applying the change of variables technique, the new distribution is obtained:

f(t,u) = ¢p(w,v) IJI , (13)

where J is the Jacobian determinant of the transformation,

4

Page 11: Statistical Computation of Tolerance Limits

Ow Ow

igt i3uJ=

onv onv

Ot t)u

Consider the transformation w = tul,/V- S, v = u 2

_vm= 0

_t

_Vm=2u ._u

The Jacobian is obtained

(14)

Therefore,

1 --_" ,F(_D2_ e _)f(t,u) = _ e v

(15)

The noncentral t-distribution is obtained by integrating over u from 0 to oo

¢tu 8_2to u 2

fo -_TV- 1" v-1 ---2 Uf(t) 1 e u e p du .

-- X_ 12

(16)

Equation (16), the density function, is integrated with respect to t from minus infinity to t to give thecumulative distribution function:

F(t;v,_5) = Pr{Tv < t} - fo G[ tU - eS) uk,/Vv-i G'(u)du , (17)

where

a'(x)- i e-_ ,

and

G(x) = fx__**G'(t)dt .

Page 12: Statistical Computation of Tolerance Limits

Thedistributionhasthefollowing properties:

Pr{Tv(8 ) < to} = 1-Pr{Tv(-¢5 ) < to} ,

Pr{Tv(8) < O} = G(-5).

Equation (17) has been formulated in one of the computer codes to evaluate the one-sided k fac-

tors, but the listing of the code for this method is not included.

Method B (New Theo_)

For the one-sided tolerance limits, the probability equation involves the form

Pr((-_)<-Kp,(-_)>Kp)=y . (18)

The joint probability is calculated about the standard normally distributed random variable

z =/ff (X-/.t)/cr and the random variable w = slot. One can approximate or, the true standard deviation, by

s, the sample standard deviation. The joint probability density is integrated over the region defined by

z =1_ kw-1-_ K e . (19)

Equation (19) is designated as the shaded area of the strip as shown in figure 2.

w

0toJ-K;)

N

Figure 2. Area of integration for one-sided tolerance limits.

Kp/k is located at the vertex on the w-axis and -Kp _ is at w = 0 On the z-axis. The shaded area is

integrated to give the summation of the elements. W is the chi-square distribution with v degrees of free-

dom, and z is a standard normal variable. In the one-sided case, the joint distribution of w and z is

derived in the following form:

I = 2 ff _ w(V-1) e 2

Let w = x/ dV. Then dw = dx/ dV .

F

6

Page 13: Statistical Computation of Tolerance Limits

Substitutingtheaboverelationsintoequation(20)resultsin

where

e-_7"

l=2f: ± dx (21)

7.2

f:**e-Tdz¢ (Y) = 2,_-Y "

After those manipulations, equation (21) can be expressed in the final form

X 2

f-1--r ¢[:n (kw-Xp)],_ (22)= __ x (v-l) eI

&

Equation (22) is programmed in the program code which is listed in appendix C 1.

Two-Sided Tolerance Limits

Method A

From method A described for the one-sided tolerance limits, equation (17) is readily imple-

mented as a summation for a set of lower and upper limits of the integrals to represent the two-sided

tolerance limits. In terms of the tolerance interval, a proportion of a distribution is constructed as a frac-

tion from which the sample is drawn. Let wl and w2 constitute a two-sided normal distribution with zero

means and unit variances. Also, let v be distributed independent of the w' s and let v obtain a square root

of a chi-square distribution with v degrees of freedom. Consequently, it follows that the expressions

(wl+S1)/v and (w2+_)/v have noncentral t-distributions with v degrees of freedom and noncentrality

parameters 81 and 62.

A two-sided noncentral t-distribution is, therefore, defined as the joint distribution of (wl+gl)/V

and (w2+62)lv. A random sample Xl, x2, x3 ..... xn from a normal distribution is assumed. Values of k fac-

tor are assigned from which tolerance limits x-ks (lower limit) and x+ks (upper limit) are computed,

specifying with probability that no more than the proportion Pl of the normal population is below F-ks

and no more than the proportion P2 is above :_+ks.

Accordingly, equation (17) is written in the following form for a set of lower (0,R) and upper

(R,oo) limits for two-sided noncentral t cumulative distribution function:

and

F(t,g;O,R) =

F(t,g;R,_) =

foR G[ tU _ g] u V-l G'(u) du

g] duf: .

(23)

(24)

Page 14: Statistical Computation of Tolerance Limits

Thus,summationof equations(23)and(24)yields

Pr {Tv < tl_} = F(t,g;O,R) = F(t,g;R,oo) . (25)

Method B (New Theory)

Dealing with a problem of solving the tolerance factor k based on the given probability and pro-

portion after the iterative process for the two-sided tolerance limits has the following form,

where

O(k) = f/ tp(z)Q[w(z)]dz ,

4/_)_ e -V_-dx

(26)

(27)

is the chi distribution and

_ 1 .d¢p(z) - _ e- 2 ,

(28)

is the standard normal probability de0sity (zero mean and unit standard deviation). Derivation of the chi

distribution is described in appendix A.

In equation (27), the lower limit of the integral, w(z), needs to be determined. The probability is

such that the quantities (L-/l)/cr and (U-la)/trexceed Kp with the proportion P being at least p, namely,

: Prob {G[(U-lz)la]-G[(L-lz)la] > p } . (29)

Equation (29) is evaluated by integrating the joint density of z and w over the shaded area in figure 3.

/,Iv

Kp/kJ

v Z

Figure 3. Area of integration for two-sided lower limits.

E

8I::

7

Page 15: Statistical Computation of Tolerance Limits

Kflk is represented at the vertex on w-axis for the lower limit (parabolic curve). The area is inte-grated with respect to z, thus summing the area elements into a vertical strip extending from the bound-ing curve of the lower limit upwards. For any value of z, a strip is defined along the line

Z = g-ff Kp -/'ff kw and another line z =/'_ Kp + 1"ffkw. So, let

(U-l.t)ltr = Kp=---_ + kw , (3O)

and

(L-It)1 cr = Kp = --_ - kw .(31)

Kp is defined by

,and the values of Kp for one- and two-sided cases are tabulated in appendices B1 and B2.

Using equations (30) and (31), the function for the lower limit becomes

f(z,w) = G[(U-I.t )l tr]-G[(L-l.t )l tr]-p = 0 ,

or

:<z,w)=C ÷kw)-C-kw)-p=O.

Equation (32) is, for some function f(z,w), the total or exact differential

(32)

Of Ofdf = -_zdz + _-_dw , (33)

ofv,._ and _w are the partial derivatives of f with respect to z and w, respectively. Then equationwhere

(32) may be written df= O. Rearranging equation (33) to obtain a differential equation

_fdw Oz

3w

3f__ _1 [e-(_ +k_)_/2- e-{_- _} _I2]. _ ] ,

=k[ e-(_+_)2r_+e-(_-_)_a]J"

THUS,

__ 0fSubstituting these values of and _ into equation (34) gives a final expression

(34)

(35)

(36)

9

Page 16: Statistical Computation of Tolerance Limits

dw = I___L_[e-(_+_2a-e-{_ -_)_t2] (37)

The hyperbolic tangent function of u is defined by the formula

tanh u = e-"-e-" (38)e-U+e-U .

Substitution of equation (38) yields the differential expression for the lower limit

dw l__ tanh (.__n kw) (39)dz - kl"ff

The methods for obtaining numerical solutions to differential equations and for computing the

integrals by numerical methods in the computer codes reduce equation (39) to

w = w(z) . (40)

The values of w(z) are applied to the lower limit of the integral of equation (27) for computation.

The computer code for this method is listed in appendix C2.

NUMERICAL RESULTS

A method for one-sided tolerance limits and another method for two-sided tolerance limits have

been devised and enhanced, using a new theory, for the exact computation of tolerance factors k. Some

tables of tolerance factors k have been generated to illustrate the exact results.

The k data are provided, for one-sided case, with the following parameters of all combinations:

Tables 1 through 3

7= 0.50, 0.75, 0.90

p = 0.50, 0.55, 0.60, 0.65, 0.70, 0.75, 0.80, 0.8413, 0.85, 0.90, 0.95, 0.975, 0.9773, 0.99, 0.9987,0.999, 0.9999, 0.999968, 0.99999

n = 2(1)50

Tables 4 and 5

)'= 0.95, 0.99

p = 0.50, 0.75, 0.90, 0.95, 0.99, 0.999, 0.9999, 0.99999

n = 2(1)10

and for two-sided case:

10

r_

_=

Page 17: Statistical Computation of Tolerance Limits

Tables 6 through 8

V= 0.50, 0.75, 0.90

p = 0.50, 0.55, 0.60, 0.65, 0.6827, 0.70, 0.75, 0.80, 0.85, 0.90, 0.95, 0.9545, 0.975, 0.99, 0.9973,

0.999, 0.9999, 0.999937, 0.99999

n = 2(1)50

T= 0.95, 0.99

p = 0.50, 0.75, 0.90, 0.95, 0.99, 0.999, 0.9999, 0.99999

n =2(1)10.

Methods A and B for the one- and two-sided cases have involved several different algorithms

needed for numerically integrating, differentiating, and iteratively root-solving the equations to obtainthe exact solutions for the tolerance factors k. In method A, the Pegasus method with an estimated order

of convergence superior to a secant method and the more accurate 20-point Gaussian quadrature proce-

dure have been employed along with some other algorithms for numerical solutions.

A procedure for method B uses the functions of normal density, normal distribution and inversenormal distribution, calculation of factorial, secant method, Simpson method for numerical integration,

and the third-order Runge-Kutta method for numerical solutions to differential equations. The Runge-

Kutta method requires three derivative evaluations per step, which has an accumulated truncation error

proportional to (Ax) 3. Those Pegasus and secant methods require input of good initial estimates in order

to solve a root-finding problem f(x) = 0.

A comparison of approximate and exact results for the two-sided tolerance factor k for n = 2 and

10 is given in table 11 with confidence level ),and proportion p.

Based on table 11, the approximate data for n = 2 differ from the exact data by at most 3.18 per-

cent. But as n increases, the error percentage decreases to less than 1 percent, as the n = 10 data can

verify.

11

Page 18: Statistical Computation of Tolerance Limits

Table 1. One-sided k.

P r ( Tv < k ,/-ff l K p ,/-ff) = )', )'=0.50

P P P P P P P P P P0.50 0.55 0.60 0.65 0.70 0.75 0.80 0.8413 0.85 0.90tl

234

56789

10111213

14151617

181920212223242526272829303132333435363738

394041424344454647484950

0.000010.000000.000_

0.000000.000000.000000.000000.000000.000000.000000.000030.00300O.O0(g)O0.00(_0.000000.000000.000000.000000.000000.000000.000000.000_0.000000.000000.000000.000000.00(00.000000.000000.000000.00(0

0.000000.000000.000000.000000.000000.000000.00(00.00000

0.000000.00(00.000000.000000.000000.000000.000000.000000.000000.00000

0.157900.141940.136490.133760.132130.131040.130270.129690.129240.128890.128600.128350.128150.127970.127820.127680.127570.127460.127370.127280.127210.127140.127080.127020.126970.12692

0.126870.126830.126790.126760.12672

0.126690.126660.126630.126600.126580.126550.126530.126510.126490.126470.126450.126440.12642

0.126400.126390.126380.126360.12635

0.320390.286730.275460.269850.266500.264290.262710.261530.260620.259880.259290.258790.258380.258020.257710.257440.257200.256980.256790.256620.256470.256330.256200.256080.255980.255880.255780.255700.255620.255540.255470.255410.255350.255290.255240.255180.255140.255090.255050.255010.254970.254930.254890.254860.254830.254800.254770.254740.25471

0.49221

0.437430.419590.410810.405590.402140.399690.397860.396440.395310.394390.393620.392980.392420.391940.391520.391150".39082

0.390530.390270.390030.389810.389620.389430.389270.389110.388970.388840.388720.388600.388500.388400.388300.388210.388130.388050.387980.387910.387840.387770.387710.387660.387600.387550.387500.387410.387400.387360.38732

0.679000.59798

0.572460.560020.552680.547840.544410.541860.539880.538300.537020.53595

0.535050.534280.533610.533030.532520.53206

0.531650.53129

0.530960.530660.530380.530130.529900.529690.529490.529310.529140.528980.528830.528690.528560.528440.528320.528210.528110.528010.527920.527830.527740.527660.527590.527520.527450.527380.527320.527260.52720

0.887370.77325

0.738480.721740.711920.70548

0.700920.69753

0.694910.692820.691120.689710._852

0.687500.686620.685860.685180.684580.684040.683560.683120.682730.682360.682030.681730.681450.681190.680950.680720.680520.68032

0.680140.679960.679800.679650.679510.67937

0.679240.679120.679000.678890.678790.678690.678590.678500.678420.678330.678250.67817

1.127010.970660.924540.902600.889810.881450.875550.871170.867790.865100.862910.861100.859570.85826

0.857130.856140.855270.854500.853810.853200.852640.852130.851660.851240.850850.850490.850160.849850.849560.849300.84904

0.848810.848590.848380.848 190.848000.84783

0.847660.847510.847360.847220.847080.846960.846830.846720.846610.846500.846400.84630

1.360221.159621.101911.074721.058951.048661.041421.036061.031921.028631.025961.023741.021871.020281.018901.017701.016641.015701.014861.014101.013421.012801.012241.011721.01125

1.010811.010411.010031.009681.009361.009051.00876

1.008501.008241.008011.007781.007571.007371.007181.007001.006831.00666

1.006511.006361.006221.006081.005951.005821.00571

1.414471.203251.142791.114351.097871.087131.079581.073981.069661.066241.063451.061141.059191.057531.056091.054841.053731.052751.051881.05109

1.05038

1.04974

1.049151.048611.04812

1.047661.047241.046851.046481.046141.045831.045531.045251.044991.044741.044511.044281.044081.043881.043691.043511.043341.04318

1.043021.042881.042741.042601.042471.04234

1.784301.498541.418931.381871.360511.346641.336901.329701.324151.319751.316181.313211.310721.308591.306751.305141.303731.302481.301361.300351.299441.298621.297871.297181.296551.295971.295431.294931.294461.294031.293621.293241.292891.292551.292241.291941.291661.291391.291141.290901.290671.290451.290241.290041.289861.289681.289511.289341.28919

12

Page 19: Statistical Computation of Tolerance Limits

Table 1. One-sidedk (continued).

Pr(Tv<k,rfflKp1"ff)=_', y= 0.50

234

56789

1011121314151617181920212223242526272829303132333435363738

394041424344

454647484950

P0.95

2.338641.938351.829451.779221.750411.731741.718661.70900

1.701571.695691.690901.68694

1.683611.680761.678301.676161.674271.672601.671111.669771.668561.66746

1.666461.665541.664701.663921.663211.662541.661921.661341.660801.660301.659821.659371.658951.658561.65818

1.657821.657491.657171.656861.656571.65630

1.656041.655781.655541.655321.655091.65488

P

0.975

2.819722.320572.186202.124462.089112.066232.050232.03841

2.029322.022122.016282.011442.00736

2.003882.000881.998261.995961.993921.99210

1.990461.988991.987641.986421.985301.984281.983331.982451.981 641.980881.980181.979521.978901.978321.97778

1.977261.976781.976321.975881.975481.975081.974711.974361.974021.973701.973401.973101.972821.972561.97229

P0.9773

2.880622.369062.231482.168282.132102.108692.092312.080222.07092

2.063562.057572.052622.04845

2.044892.041822.039142.036792.034702.032842.031162.029652.02828

2.027032.02588

2.024832.023862.022972.022142.021362.020642.019972.019332.018742.018182.017662.017162.016692.016252.015832.015432.015052.014692.014342.014022.013702.013402.013112.012852.01259

P0.99

3.376052.764542.600882.525832.482902.455142.435722.421392.410382.401652.394562.388702.38376

2.379552.375912.372742.369952.367482.365272.363292.361502.35987

2.358392.35704

2.355792.354642.353582.352602.351682.350832.350032.349282.348582.347922.347302.346712.346162.345632.345142.344662.344212.343782.343382.342992.342622.342262.341932.341602.34128

P0.9987

4.391243.57922

3.362613.263383.206663.16998

3.144343.125413.110873.099343.089993.082243.07572

3.070163.06536

3.061173.057493.054223.051313.048693.046333.044193.042233.040443.03880

3.037283.035883.034583.033383.032253.031193.030213.029283.028413.027593.026813.026083.025393.024733.024103.023513.022953.022413.021903.021413.020943.020493.020073.01966

P0.999

4.526643.688173.46454

3.362113.303543.265683.23922

3.219673.204663.192763.183103.175103.168373.162633.157673.153353.149553.146183.143173.140473.138033.135823.133803.131953.130263.12869

3.127243.125903.124663.123493.122403.121383.120433.119543.118693.117883.117123.116413.115733.115093.114473.113893.113333.112803.112303.111823.111353.110913.11057

P

0.9999

5.468274.447034.174784.050083.978803.932713.900473.87669

3.858403.843923.832173.82246

3.814173.807233.801223.795873.791313.787173.783523.780223.777313.774563.772063.769883.767833.765873.76408

3.762513.760973.759543.758223.756993.755853.754743.753673.752703.751813.750953.750103.749303.748563.747873.747193.746533.745913.745333.744783.744243.74368

P0.999968

5.888114.785834.492024.357434.280474.230724.195924.170244.150504.134864.122164.11165

4.102804.095254.088734.083064.078054.07362

4.069674.066114.063044.060014.057364.054944.052734.050704.048844.047144.045594.044204.042974.041914.041044.040404.040014.03993

4.035464.034554.033694.032894.032164.03149

4.030904.030384.029964.029664.029484.02946

4.02963

P0.99999

6.283495.10513

4.790974.647084.564694.511814.474294.447034.425774.409264.395324.384594.37461

4.366814.360024.353424.348444.343894.339414.335514.332484.32903

4.326294.323734.321494.318924.316784.315234.313584.311664.309994.308794.307614.30619

4.304804.303754.302884.301894.300774.299784.299024.29832

4.297514.296664.295914.295304.294724.294084.29322

13

Page 20: Statistical Computation of Tolerance Limits

Table 2. One-sided k.

Pr(Tv < k l'ff l Kp,/-ff) = y, y=0.75

23456789

1011121314

151617

18192021222324252627282930313233343536

3738394041

424344i45!4647i48149 _

50

P0.50

0,70712

0.471400.382450.331250.296670.27121

0.251430.235460.222220.211000.201340.192890.185430.178780.172800.167380.162440.157920.153760.149910.146330.143000.139890.136970.13423

0.131640.129200.126900.124710.122630.12065

0.118760.116960.115240.113590.11202

0.110500.10905

0.107650.106300.10501

0.103760.102550.10138

0.100260.099170.098110.097090.09610

P0.55

0.941300.639290.53421

0.475840.437220.40917

0.387570.370280,356020.343990.333660.324680.316760.309720.303400.297680.292490.287730.283360.279330.275580.272100.268850.265800.262940.260250.257710.255310.253030.250870.248820.246860.244990.243210.241500.239870.238300.236800.235350.233960.232620.231330.230080,228880.227720.226590.225510.224450.22343

P0.60

1.202910.818290.693750.626820.583380.552230.528490.509600.494120.481120.470000.460360.451890.444370.437640.431560.426050,421010.416390.412120.408170.404500.401080.397870.394870.392040.389370.386850.384470.382210.380060.378010.376060.374190.372410.370700.369070.367500.365990.364540.363150.361800.360500.359250.358040,356870.355740.354650,35359

P

0.65

1.497941.011910.864080.786960.737810.703010.676710.655940.639000.624840.612780.602350.593220.585130.577900.571400.565500.560120.555180.550640.546440.542540.538900.535500.532320.529320.526500.523840.521320.518930.516660.514500.512450.510480.508610.506810,505090.503440.501860.500330.498870.497460.496090.494780.493510.492290.491 I00.489960.48884

P0.70

1.834801.225081.049410.960200.904280.865130.835800.812780.794110.778580.765390.754020.744090.735320.727500.72047

0.714110.708310.703010.698130.693620.689440.685550.681910.678510.675310.672310.669470.666780.664240.661820.659530.657340.655250.653260.651360.649530.647780.646100.644490.642940.641440.640000.638610,637270.635980.634720.633510.63234

P

0.75

2.224761.464341.255311.151661.087661.043331.010380.984680.963940.946750.932210.91971

0.908820.899220.890690.883020.87610

0.869810.86406

0.858770.853890.849370.845160.84124

0.837570.834130.830890.827830.824950.822210.81962

0.817160.814810.81258

0.810440.80840

0.806450.80458

0.802780.80105

0.799400.797800.796260.79478079334

0.791960.790630.789330.78808

P0.80

2.686051.740271.490741.369601.295811.245201.207851,178891,155621.136421.120231.106361.09429

1.083691.074271.065831.05822

1.051311.045001.039211.033881.028941.024341.020071.016071.01232

1.008791.005471.002330.999360.99655

0.993880.991340.988910.986600.984390.982280.980250.978310.97644

0.974650.972930.971270.969670.96812

0.966630.965190.963800.96245

P0.8413

3.144132.009401.718921.580101.496411.439441.397631.365361.339521.318271.300401.285111.271851.260211.249891.240661.23234

1,224801.217921.211621.205811.200441.195451.190801.186461.18240

1.178581.174981.171581.168371.165331.162441.159691.157081.1 54581.152201.149921.147731.145641.14363

1.141701.139841.138051.136331.13466

1.133061.131511.130011.12856

P

0.85

3.251692.07212

1.771941.628931.542901.484411.441551.408491.382051.360301.342031.326411.312861.300981.290441.281021.272541.264841.257831.251401.245481.240001.234921.230191.225771.221621.217731.214071.210611.207341.204241.201301.198511.195841.193301.190881.188561.186331.184201.182161.180191.178301.176481.174731.173041.171411.169831.168311.16684

14 E

Page 21: Statistical Computation of Tolerance Limits

Table 2. One-sided k (continued).

Pr(Tv<k,/'fflKp1-_}=?', y= 0.75

2

34

56789

1011121314151617181920212223!24425 _26'27'28'29

3031323334353637383940

41424344

454647484950

P0.90

3.992642.501232.13373

1.961611.859231.790211.739941.701381.670671.645501.624421.606441.590891.577271.565221.554461.544791.536031.528061.520761.514041.507831.502081.496731.491731.487051.482661.478531.474631.470951.467461.464151.461011.45801

1.455161.452431.449831.447341.444951.44265

1.440451.438341.436301.434341.432441.43062

1.428861.427151.42551

P0.95

5.121343.151742.680522.46331

2.335522.250062.188232.141032.103602.073052.047532.025832.007111.990741.97629

1.963421.951861.941411.931901.923211.915221.907851.901031.894681.888761.883231.878031.87315

1.868551.864201.860091.856191.852491.848961.845611.842401.839341.836411.833601.830911.828331.825851.823461.821161.818941.816801.814741.812751.81082

P P0.975 0.9773

6.11237 6.23838

3.72465 3.797713.16171 3.223082.90438 2.960622.75387 2.807212.65367 2.705112.58143 2.631532.52645 2.575552.48296 2.531282.44752 2.495222.41799 2.465162.39291 2.439652.37130 2.417672.35244 2.398492.33581 2.381572.32100 2.366522.30772 2.353012.29572 2.340812.28482 2.329732.27486 2.319602.26571 2.310302.25727 2.301732.24946 2.293792.24221 2.286422.23544 2.279552.22912 2.273122.22319 2.267102.21762 2.261442.21237 2.256102.20742 2.251072.20273 2.246312.19828 2.241792.19406 2.237512.19005 2.233432.18623 2.229542.18259 2.225842.17910 2.222312.17577 2.218932.17258 2.21569

2.16952 2.212582.16659 2.209592.16377 2.206722.16105 2.203972.15844 2.201322.15592 2.198772.15350 2.196312.15116 2.193932.14889 2.191632.14670 2.18941

P0.99

7.268964.395983.725803.421283.243953.126303.041712.977482.926762.885512.851182.822072.797012.775162.75591

2.738792.723442.70959

2.697012.685522.674982.665262.656262.647922.64014

P0.9987

9.388525.63814

4.770464.378554.151344.001143.893463.811903.747633.695463.652103.615403.583833.556373.532173.510653.491423.474053.458243.443883.430753.418563.407273.396893.38722

P0.999

9.672515.804964.910834.507194.273274.118684.007883.923983.857883.804243.759643.721943.68947

3.661223.636373.614263.594483.576653.560453.545663.532203.519663.508043.49739

3_48744

P

0.9999

11.65011

6.969745.891545.405845.125054.939714.807224.706884.627964.563964.510594.465934.427254.393514.364274.33766

4.314214.293284.273764.25605

4.240674.225534.211514.198914.18764

P0.999968

12.533347.491076.330365.80826

5.506475.307495.165165.057364.972754.904064.847034.798864.75630

4.721384.690844.661474.636284.613844.593054.574224.557364.541564.526124.513064.50072

2.632862.62605

2.619642.613622.607932.602542.597442.592612.588002.583622.579442.57544

2.571632.567982.564492.561112.557882.554762.551782.548912.546142.543462.540862.53836

3.378113.369573.361593.354133.347023.340093.333843.328033.322453.316903.311463.306303.30176

3.297423.293273.288903.284773.280693.277043.273653.270393.267163.263713.26051

3.478113.469323.461133.453483.446243.439273.432603.426583.420823.415303.40978

3.404653.399683.39519

3.390833.386553.382273.378223.37440

3.370853.367433.364043.360613.35739

4.17639 4.488624.16542 4.476984.15560 4.466864.14713 4.457564.13884 4.449164.13017 4.439404.12131 4.430054.11486 4.423264.10847 4.416314.10270 4.409564.09523 4.401924.08847 4.39463

4.08243 4.388734.07813 4.383694.07344 4.378544.06854 4.372604.06285 4.367504.05732 4.361474.05268 4.357254.04902 4.352584.04564 4.348744.04185 4.343924.03745 4.339884.03308 4.33533

P0.99999

13.365887.982856.744536.188125.866425.654445.502825.388155.298175.224975.164265.113035.069325.030614.997344.96687

4.940034.91651

4.894204.874114.856494.839844.822734.809174.79647

4.783414.770514.759974.750414.742254.731124.720354.712644.706804.699944.690584.682824.676724.67177

4.666934.660264.654944.64668

4.643664.638094.635884.629584.625414.61956

15

Page 22: Statistical Computation of Tolerance Limits

Table 3. One-sided k.

P r ( Tv < k ,f-ff l K p /-ff} = 7 , ?'=0.90

2

3456789

1011121314

1516171819202122i

23]2425!26

2728!29!

303132333435363738394041424344454647

48 i491

50

P P P P P P P P P0.50 0.55 0.60 0.65 0.70 0.75 0.80 0.8413 0.85

i ""

2.17634

1.088660.818870.685670.602530.544180.500250.465610.437350.41373

0.393590.376150.36085

0.347280.335150.324210.314280.305210.296890.289210.282110.275500.269330.263570.258160.253070.248270.243730.239430.235360.231480.227790.224280.220920.217700.214620.211680.208840.206120.203510.200990.198560.196220.193960.191770.189660.187610.18563

0.18372

2.72056

1.334361.012150.858230.764110.698980.650460.612500.581730.556140.534420.515680.49930

0.484810.471880.460250.449710.440110.431310.423210.415710.40875

0.402270.39621

0.390530.385200.380170.375420.370930.366670.362620.358770.355100.351600.348250.34505

0.341980.339040.336210.333490.330870.32835

0.325920.323570.321310.319120.317000.314950.31297

3.343081.602531.21950

1.041660.934870.861920.808080.766260.732580.704700.681130.660860.643200.62762

0.613760.601310.590050.57981

0.570440.561830.553870.546490.539620.533210.527210.521570.51627

0.511260.506530.502040.497790.493740.489880.486210.482700.479340.476120.473030.470070.467220.464490.461850.459310.456860.454490.452210.449990.447860.44578

4.056621.897971.444611.239231.117861.035890.975920.929650.892580.862040.836320.814280.795120.778270.763300.749890.737790.726800.716760.707530.699020.691150.683820.676990.670600.664610.658970.653660.648630.643880.639370.635080.631000.627110.623400.619850.616450.613200.610070.607070.604180.601410.598730.596150.593660.591260.588930.586680.58450

4.880672.228011.69301t.455761.317541.225121.158031.10659

1.065591.031951.003720.97960

0.958690.940350.924090.909550.896450.884570.873730.863790.854630.846160.838290.830960.824110.817690.811650.805960.800600.795520.790700.786130.781780.777640.773680.769910.766290.762830.759510.756320.753250.750300.747460.744720.742080.739530.737070.734690.73238

5.842562.602831.972261.697811.539891.435271.359861.302351.25673

1.219441.188251.16168

1.138711.118601.100811.084921.070641.057701.045911.035111.025181.016001.007480.999550.992150.985210.978700.972570.966780.961310.956130.951120.946540.942090.937840.933790.929910.926200.922630.919220.915940.912780.909740.906810.903980.901260.898620.89608

0.89362

6.987863.03934

2.294831.976091.794721.675541.590181.525431.474271.432611.397861.368351.34288

1.320641.301001.283491.267771.253551.240611.228771.217891.20785

1.198541.189881.181801.174241.167141.160471.154181.148231.142601.137261.132181.127351.122741.118351.114151.110131.106271.102571.099021.095611.092321.089161.086111.083161.080321.077571.07492

8.137223.468342.61005

2.247082.042271.908521.813191.741161.684441.638371.600051.567561.539581.51518

1.493661.474511.457331.441811.427701.414811.402961.39204

1.381921.372521.363751.355551.347861.340631.333821.327381.321291.315511.31003

1.304811.299841.29509

1.290561.286221.282061.278081.27425

1.270571.267031.263621.260341.257171.254111.251151.24830

8.403373.568682.683602.310212.099871.962691.865001.791251.733211.686101.646931.613731.585161.560241.538281.518741.501221.485391.471001457861.445781.434651.424341.414761.405831.397481.38964

1.382281.375341.368791.362591.356711.351131.345811.340751.335921.331311.326901.322671.318611.314721.310981.307381.303911.300571.297351.294241.291231.28832

16

Page 23: Statistical Computation of Tolerance Limits

Table3. One-sidedk (continued).

Pr(Tv<_k_lKv_)= )', )'=0.90

tt

P0.90

10.252634.258323.187962.742442.493772.332722.218662.132942.06574

2.011351.966261.928141.895401.866901.841831.819551.799601.781601.765261.750351.736671.724071.71241

1.701581.691491.682071.673241.664941.65712

1.649741.642771.636161.629881.623921.618241.612821.607641.602691.597951.593411.589041.584851.58082

1.576951.573211.56961

1.566131.562771.55952

P0.95

13.089705.311323.956453.399743.091792.893722.754212.649822.56830

2.502542.448182.402332.363042.328912.298932.272342.248562.227142.207712.190012.173782.158842.145042.132232.120312.109182.098752.088962.07975

2.071072.062852.055082.047702.040692.034012.027652.021582.015772.010212.004881.999771.994871.990151.985611.981241.97702

1.972961.969031.96523

P0.975

15.586246.243824.637053.981383.620493.389253.226893.105733.011302.935292.872542.819702.774472.735232.700802.670292.643032.618492.596262.576002.557452.540392.524622.510012.4964 12.483712.471832.460682.450202.440312.430962.422122.413722.405752.398172.390942.384042.377442.371132.365092.359292.353722.348372.343222.338272.33349

2.328882.324432.32013

P0.9773

15.904196.363004.724084.055743.688063.452573.287283.163963.067872.990532.926702.872962.826972.787072.752062.721042.693332.668392.645802.625212.606362.589022.573012.558162.544342.531442.519372.508052.497392.487352.477862.468872.460352.452252.444552.437212.430202.423502.417102.41096

2.405072.399422.393982.388762.383732.378872.37419

2.369672.36531

P0.99

18.500097.34060

5.438354.666074.242623.972113.782633.641523.531733.443493.370743.309553.257233.211883.172123.136923.105493.077213.051613.028303.006962.987342.969222.952432.936812.922242.908602.895822.883792.872452.861742.851602.841992.832872.824182.815902.808002.800462.793242.786332.779702.773332.767222.761342.755682.750222.744942.73986

2.73494

P

0.9987

23.862969.380236.928525.93969

5.399635.055744.815484.636964.498354.387104.295544.218614.152954.09597

4.046294.00213

3.962803.927483.895473.86635

3.839763.815303.792643.771773.752373.734183.717183.701323.686403.672273.658923.646363.634463.623123.612363.602033.592173.582933.573963.565373.557153.549293.541723.534433.527403.520653.514153.50788

3.50182

P0.999

24.581389.653157.129246.111215.555465.201674.954544.770974.62847

4.514094.420004.340934.273464.214944.163904.11850

4.078094.041824.008923.978983.95178

3.926613.903313.881903.862013.843313.825833.80956

3.794273.779753.766033.753143.740943.72930

3.718273.707633.697623.688033.678963.670363.661563.653383.645753.638263.631153.624143.617453.610883.60480

P0.9999

29.5865111.611238.533127.311016.645516.222445.927305.708415.538615.40210

5.290225.195875.116105.046424.985874.932024.883754.841584.802104.766654.734414.70445

4.676364.651234.628024.606014.584654.56575

4.548254.531414.513844.497984.485024.47207

4.458544.444784.431564.422114.411524.401704.390754.380584.371804.363844.355714.347064.339424.331444.32221

P0.999968

31.82294

12.570669.16226

7.849927.134086.680026.363686.128825.947795.800335.680765.578575.493935.418935.354255.296825.245155.199635.157405.118875.085225.05404

5.020574.995564.973684.947854.925134.905134.887064.86871

4.848774.833594.817854.80727

4.790514.774684.763294.751024.739754.727834.718364.707424.698094.688794.68171

4.673484.661844.652384.64034

P0.99999

33.9315913.546749.756688.35726

7.596417.111846.774106.52611

6.332016.175526.049435.940735.850735.77042

5.701915.641495.585915.53804

5.492935.449595.416445.383955.349505.321925.296775.270715.244275.225005.205465.187855.164415.149145.133135.117945.101195.086055.073835.060455.049625.036325.025285.014935.002744.995464.98802

4.980604.968834.955294.94138

17

Page 24: Statistical Computation of Tolerance Limits

Pn 0.50

2 4.464593 1.685864 1.17668

5 0.953396 0.822647 0.734458 0.669849 0.61985

10 0.57968

Table 4. One-sided k.

Pr(Tv <k1"_lKvg'ff)= Y, y= 0.95

P

0.75

11.763573.806192.617612,149691.895031.732251.617821.532201.46524

P0.90

20.581686,155264.16193

3.406633.006262.755432.581912.453762.35464

P0.95

26.258747.655955.143894.202683.707683.399473.187293,031242,91096

P

0.99

37.0945410,552737.042355.741105.061974.641724.353864.143023.98112

P

0,999

49.2743713.857159,21413

7.501876.611796.062835,687545.413355.20320

P0.9999

59.3012516.5979611.01895

8,965997.900517.244126.796236.469266.21886

P0.99999

68.0071518.9855512.5929810.24328

9.024898.274907.763487.390327.10472

Table 5. One-sided k.

Pr{Tv<_kg'51Kpg'5} = y, y=0.99

n

23456789

10

P0,50

22.509104,021052,270351,675691.373731,187821.059940.965490,89222

P0.75

58.937658.728194.715193.454112.848092.490722.253372.083141.95433

P0.90

103.0070713.99520

7.379955.361754.411083.859133.49721

3.240413.04791

P0.95

131.44022

17.370209.083436.578335,405544.727864,285253.972263.73832

P0.99

185.6286823.8960412.387338,939077.334566.41193

5.811775.388905.07374

P0.999

246.6043231.3476516.1757011.649329.549928.345737.564167.014406.60539

P0.9999

296.7162937,5327619.3274213.9065311.395469.956919.024038.368427.88102

P0.99999

340,2216142.9218522.0779215.8773313.00732

11.3640710.299079.550928.99499

18m

=

Page 25: Statistical Computation of Tolerance Limits

Table 6. Two-sided k.

Pr(Tv<kl'_lKpl'_=),, r= 0.50

23456789

10111213141516171819202122

232412526272829303132333435363738394041

424344

454647484950

P P0.50 0.55

1.24272 1.384110.94201 1.05228

0.85225 0.953080.80826 0.904360.78196 0.875180.76439 0.85568

0.75181 0.841690.74235 0.831160.73496 0.822930.72903 0.816330.72417 0.810910.72011 0.806390.71666 0.802540.71370 0.799240.71114 0.796380.70888 0.793860.70689 0.791640.70512 0.789660.70353 0.787880.70210 0.786290.70080 0.784840.69962 0.783530.69854 0.782320.69756 0.781220.69664 0.780200.69580 0.779260.69502 0.778380.69430 0.777570.69362 0.776820.69299 0.776120.69240 0.775460.69185 0.774840.69133 0.774250.69084 0.773710.69037 0.773190.68994 0.772700.68952 0.772240.68913 0.771800.68876 0.771380.68841 0.770990.68807 0.770610.68775 0.770250.68744 0.769910.68715 0.769580.68687 0.76927

0.68660 0.768970.68635 0.768690.68610 0.76841

0.68587 0.76815

P0.60

1.533241.169051.060091.006470.974310.952780.937320.925680.916580.90927

0.903270.898250.893990.890330.887150.88436

0.881900.879700.87773

0.875960.874350.872890.871550.87032

0.869190.868150.867180.866280.865440.864650.863920.863230.862590.861980.861400.860860.860340.859860.859390.858950.858540.858140.857760.857390.857050.856710.856400.856090.85580

P0.65

1.69250

1.294221.175021.116281.080981.057331.040331.027511.017481.009421.002810.997270.992570.988520.985010.981930.979200.976780.974600.972640.970860.969240.967760.966400.965150.963990.962920.961920.961000.960130.959320.958550.957840.957160.956530.955920.955360.954820.954300.953820.953350.952910.952490.952090.951700.951330.950980.950640.95032

P0.6827

1.803671.381841.255611.193351.155901.130781.11272

1.099081.088421.079841.072801.066901.061891.057581.053841.050561.047651.045061.042741.040651.038751.037021.035441.033991.032661.031421.030281.029211.028221.027301.026431.025621.024851.02413

1.023451.022811.022201.021621.021071.020551.020061.019591.019141.018711.018301.01790

1.017521.017161.01682

P0.70

1.865291.430491.300401.236211.197581.171651.153011.138931.127911.119051.11177

1.105671.100491.096041.092171.08877

1.085771.083091.08069

1.078521.076561.074771.073141.071 641.07025

1.068981.067791.066691.065661.06471

1.063811.062971.062171.061431.060721.060061.059431.058831.058261.057721.057211.056721.056261.055811.055391.054981.054591.054221.05386

P0.75

2.056701.581911.44000

1.369911.327661.29928

1.278841.263391.251291.241561.233551.226841.221141.216241.211971.208221.204911.201961.199311.196921.194751.192781.190981.189321.187791.186381.185071.183861.182721.181661.180671.179741.178861.178041.177261.176521.175831.175161.174541.173941.173381.172831.172321.171821.171351.170901.170471.170061.16966

P0.80

2.274971.755101.599991.523321.477061.445931.423501.40652

1.393211.382501.373671.366281.359991.354581.349871.345731.342071.338811.335881.333241.330841.328661.326661.324821.323131.321571.320121.318771.317511.316341.315241.314211.313241.312321.311461.310641.309871.309141.308441.30778

1.307151.306551.305981.305431.30491

1.304411.303931.303471.30303

P0.85

2.535081.96210

1.791581.707271.656351.622051.597291.578541.563831.55197

1.542191.534001.527021.521021.515791.51119

1.507121.503491.500241.497301.49463

1.492201.489971.487931.486041.48430

1.482681.481181.479781.478471.477241.476091.475001.473981.473021.472111.471241.470431.469651.468911.468211.467541.466901.466281.465701.46514

1.464611.464091.46360

19

Page 26: Statistical Computation of Tolerance Limits

Table 6. Two-sided k (continued).

Pr(Tv<k_lKp_}=_', _'= 0.50

tl

23456789

10111213141516171819

202122

232425262728293031323334353637383940414243444546 I

47484950

P P P P P P P P P P

0.90 0.95 0.9545 0.975 0.99 0.9973 0.999 0.9999 0.999937 0.99999

2.869352.228912.039011.945171.888461.850211.822571.801611.785141.771851.760891.751701.743861,737111.731231.726051.721471.71738

1.713711.710391.707381.704641,702121.699811,697681.695711.693891.692181,690601.689121.687731.686421.685191.684041.682941.681911,680931,680011.679131.678291.677491.676731.67600

1.675311.674651.674011.673401,672821.67226

3.375602.634232.415742.307962.242822.198842.167022.142862.123862.108502.095822.085162.076082.068242.061402.055382.050052.045282.041002.037132.033622.030412.027482.024772.022282.019982.017842.015842.013982.012252.010622.009082.007642.006292.005002.003792.002642.001552.000511.999531.998591.997691.996841.99602

1.995241.994491.993781.993091.99243

3.439422.685422.463382.353882.287692.243012.210682.186132.166822.151212.138312,127482.118242,110262.103312.097192.091762.086922.082562.078622.075042.071782.068792.066042.063512.061162.058982.056952.055062.05329

2.051632.050072.048602.047222.045912.044682.04350

2.042392.041342.040332.039382.038462.037602,03676

2.035972.035212.03448

2.033782.03310

3.822222,992762.749612.629922.557622.508812.473472.446622.425482.408382.394252.382372.372232.363472.355832.349102.343132,337792.332992.328652.324712.321112,317812.314782,311982.309382.306982.304732.302642.30068

2,298842.297122.295502.293962.292522.291152.289852.28862

2.287452.286342.285282.284262.283302.28238

2.281492.280652.279842.27906

2.27831

4.347623.415353.143693.010362.929912.875622.836312.806422.78288

2.763822.748062.734792.723472.71368

2.705132.697602.690912.684932.679542.674682.670252.666212.662502.659092.655942.653022.650312.647782.645422.643212.641142.63920

2.637362.63563

2.634002.632452.630982.62959

2.628272.627012.625812.624672.623582.622532.621532.620572.619652.618772.61793

5.007593.947093.640183.490 t 13.399753.338823.294723.261193.23476

3.213373.195663.180753.168013,156993.147363,138873.131323.124573.118493.112993.107983.103413.099213.095343.091773.088463.085393.082523.079843.077333.074983.07277

3.070683.068713.066853.065093.063423.06184

3.060333.058893.057523.056223.054973.053783.052643.051543.050493.04949

3.04852

5.456374.309103.978473.817233.720283.654973.607713.571783.54348

3.520553.501573.485583.471923.460103.449773.440663.432553.425303.418773.412853.407473.402553.398033.393873.390033.38646

3.383153.380063.377173.374473.371933.369543.367293.365173.363163.361263.359463.357743.356113.354563.353083,351673.350323,349033.347803.346613.345483.344393.34334

6,376975.052424.67364

4.489824.379644,305574.252034.211374.17934

4.153394.131924.113834.098364.084974.073264.062934.053744.045514.038104.031384.025264.019674.014534.009794.005424.001363.997583.994053.990763.987673.984773.982053.979473.977043.974753.972573.970513.968543.966683.964903.963203.961583.960043.958563.957143.955783.954473.953223.95202

6.544065.187434,79995

4.612084.499534.423894.369244.327744.29504

4.268574.246664.228194.212414.198754.186804.176254.166874.158474.150904.144044.137804.132084.126844.122004.117534.113384.109524.105924.102564.099414.096444.093664.091034.088554.086204.083974.081864.079864.077954.076134.074404.072744,071164.069644.068194.066804.065474.064194.06296

7.179475.700985.280585.07736

4.955884.874364.815514.770854.735694.707234.683674.663824.646864.632174.619334.607994.597904.588864.580724.573344.566624.560474.554824.549614.544794.540324.536164.532284.528664.525254.522064.519054.516214.513534.511004.508604.506324.504154.502094.500124.498254.496464.494744.493114.491544.490034.488594.487204.48586

20

Page 27: Statistical Computation of Tolerance Limits

P

n 0.50

2 2.673263 1.491234 1.210745 1.08297

6 1.008997 0.96038

8 0.9258091 0.89984

10 0.87957111 0.8632612 0.8498213 0.8385414 0.8289115 0.8205916 0.8133217 0.8069018 0.8011919 0.7960720 0.7914521 0.7872522 0.7834323 0.7799224 0.7767025 0.7737226 0.7709627 0.7683928 0.7659929 0.7637530 0.7616431 0.7596732 0.7578033 0.7560534 0.7543835 0.7528136 0.7513137 0.7498938 0.7485439 0.7472540 0.7460241 0.7448442 0.7437143 0.7426444 0.7416045 0.7406146 0.7396547 0.73873

48 0.7378549 0.7370050 0.73618

Table 7. Two-sided k.

Pr(Tv<kl'_lKp1-ff)=?', y= 0,75

P0.55

2.972341.66318

1.352581.210891.128741.074691.036211.00729

0.984700.966510.951520.938920.928170.918880.910760.90359

0.897200.89148

0.886320.881630.877360.873440.869830.866500.863410.86053

0.857850.855340.852990.850780.848690.846730.844870.843100.841430.839840.838330.836880.835510.83419

0.832930.831720.830560.829450.828380.827350.826360.825410.82449

P

0.60

3.287591.844991.50287

1.346641.255951.196201.153621.121601.096561.076391.059761.045781.033851.023531.014511.006540.999450.993090.987350.982140.977390.97303

0.969020.965310.961870.958680.955690.95290

0.950280.947820.945510.943320.941250.939280.937420.935650.933970.932360.930830.929360.927960.926610.925320.924080.922900.921750.920650.919590.91856

P

0.65

3.62408

2.039601.664071.492461.392711.326931.28000

1.244681.217051.194771.176391.160941.14774

1.136331.126341.117521.109671.102631.096271.090501.085241.080411.075961.071851.068041.064501.061191.058101.055201.052471.049901.047471.045171.043001.040931.038971.037101.035321.03362

1.031991.030431.028941.027511.026141.02482

1.023551.022331.021151.02001

P

0.6827

3.858882.175681.77698

1.594701.488681.418721.368771.331161.30172

1.277981.258381.241901.227821.215641.204991.195581.187191.179671.172881.166721.16110

1.155941.151191.146801.142731.138941.13541

1.132101.129001.126081.123331.120741.11828

1.115961.113751.111651.109651.107751.105931.104191.102531.100931.099401.097931.096521.095171.093861.092601.09138

P

0.70

3.989022.251211.839691.65152

1.542051.469771.41816

1.379291.348851.324291.304021.286981.272411.259811.248781.239041.230361.222581.215551.209171.203341.198001.193081.188541.184321.180401.176741.173311.170101.167081.164241.161551.159011.156601.154311.152141.150061.14809

1.146211.144411.142681.141031.139441.137921.136461.135061.133701.132401.13114

P0.75

4.393152.48613

2.035011.828661.708511.629111.572351.52957

1.496041.468981.446621.427811.411731.39782

1.385631.374871.365281.356671.34890

1.341841.335401.329491.324041.319011.314351.31001

1.305951.302161.298601.295261.292101.289131.286311.283641.281111.278701.276401.274221.272131.270131.268221.266391.264631.262951.261331.259771.258271.256821.25542

P P

0.80 0.85

4.85395 5.403052.75463 3.075352.25863 2.526192.03173 2.275001.89952 2.12855

1.81206 2.031601.74949 1.962181.70228 1.909751.66526 1.868601.63536 1.835331.61064 1.807821.58983 1.784641.57203 1.764811.55662 1.747631.54313 1.732581.53120 1.719261.52056 1.707401.51102 1.696741.50240 1.687111.49457 1.678361.48742 1.670371.48086 1.663041.47482 1.656281.46923 1.650031.46405 1.644241.45923 1.638841.45473 1.633811.45052 1.629091.44656 1.624661.44284 1.620501.43934 1.616581.43603 1.612881.43290 1.609371.42994 1.606051.42712 1.602891.42444 1.599891.42189 1.597041.41946 1.594311.41714 1.591711.41492 1.589221.41279 1.586841.41076 1.584561.40880 1.582371.40693 1.580271.40512 1.578251.40339 1.576301.40172 1.574431.40011 1.572631.39856 1.57089

21

Page 28: Statistical Computation of Tolerance Limits

Table 7. Two-sided k (continued).

P r ( Tv < k g'ff l K p1"ff ) = )" , )'=0.75

n

2

3456789

10111213

14151617181920212223242526272829303132333435!3637

38394041424344

4546474849

50

|

P0.90

6.10874

3.488532.871482.589362.424812.315792.237662.178602.132202.094672.063602.037402.01498

1.995541.978491.963411.949961.937881.92696

1.917041.907971.899641.891971.884881.878291.872161.866431.861071.856041.85131

1.846851.842631.838641.834861.831271.82786

1.824601.82150

1.818541.81571

1.813001.810401.807901.805511.803211.800991.798861.79680

1.79482

P0.95

7.177614.116063.396873.068362.876732.74969

2.658562.589612.535382.491482.455102.424392.398092.375262.355242.337512.321692.307472.294612.282912.272222.26240

2.253352.24498

2.237202.229962.223202.216862.210912.205322.200042.195052.190332.185862.181612.177562.173712.170042.166522.163172.159952.156872.153922.151082.148352.145722.143192.140752.13840

P0.9545

7.312384.195303.463283.128962.933942.804642.71189

2.641702.586502.541792.504752.47348

2.446702.423442.403052.384992.368872.354392.341282.329362.318472.308462.299242.290702.282782.275402.268502.262042.255982.250282.244902.239812.235002.230442.226102.221982.218052.214312.210732.207302.204032.200882.197872.194982.192192.18951

2.186932.184442.18205

P0.975

8.120794.671103.862323.493243.277983.135243.032802.955252.894222.844772.803772.769142.73946

2.713692.691072.671042.653152.637062.622512.60926

2.597162.586032.575772.566282.557462.549242.541572.534382.527632.521272.515282.50961

2.504252.499162.494332.489732.485352.481172.477182.473362.469712.466202.462842.459612.456502.453512.450632.44785

2.44517

P0.99

9.230625.325384.411663.995163.752343.591323.475733.388173.319243.263353.216993.177823.144223.115023.089393.066673.046383.028123.011602.996552.982792.97015

2.958482.947682.937652.928302.919562.911372.903682.896442.889602.883142.877032.871232.865722.860472.855472.850702.846152.841792.837612.833612.829772.826082.822522.819112.815822.812642.80958

P0.9973

10.625096.148825.103774.628044.350884.167114.03517

3.935213.85647

3.792613.739603.694793.656333.622903.593543.567503.544223.523283.504313.487033.471223.456693.443283.430863.419313.408553.398493.389063.380203.371853.363983,356533.349483.342793.336433.330383.324613.319103.313843.308813.303983.299363.294923.290653.286553.28260

3.278793.275123.27158

P0.999

11.573546.70953

5.575425.059574.759184.560044.417084.308764.223424.154184.096704.048104.00638

3.970103.938233.909953.884683.861923.841313.822543.80535

3.789553.774963.761453.748893.737173.726223.715953.706313.697223.688643.68053

3.672853.665563.658623.65203

3.645743.639743.634003.62851

3.623243.618203.613363.608703.604223.599913.595763.591753.58789

P0.9999

13.519577.861166.544765.946935.599125.368665.203245.077904.979144.899004.832454.776154.727814.685764.648794.615994.586664.560244.536294.514484.49450

4.476134.459164.443444.428814.415174.402424.390454.379214.368614.358614.349154.340184.331684.323584.315884.308534.301524.294824.288404.282254.276354.270694.265244.260004.254964.250104.245414.24088

P0.999937

13.872848.070366.720916.108245.751855.515735.346255.21784

5.116665.034554.966364.908684.859144.816054.778174.744554.714494.687414.662874.640504.620024.60119

4.583794.567674.552684.538694.525614.513344.501814.490944.480684.470984.461784.453054.444754.436854.429314.422124.415244.408664.402344.396294.390484.384894.37952

4.374344.369354.364544.35990

P

0.99999

15.216378.866257.391266.722206.333236.075625.890765.750705.640345.55078

5.476405.41347

5.359415.312395.271045.234345.201515.171945.14513

5.120705.098325.077735.058725.04109

5.024695.009404.995094.981664.969044.957154.945924.93530

4.925234.915674.906584.89793

4.889674.881794.87425

4.867034.860124.853484.847114.840984.835094.829424.823944.818674.81357

22

Page 29: Statistical Computation of Tolerance Limits

Table8. Two-sidedk.

Pr{Tv < k1"ff l Kpg'_) = )', ),=0.90

2345

6789

1011121314

1516

171819202122232425262728293031323334

35363738394041424344454647484950

P P P P P P P P P0.50 0.55 0.60 0.65 0.6827 0.70 0.75 0.80 0.85

,==,

6.808262,491851.765621.472711.313561.212991.143371.09212

1.052691.021330.995740.974420.956340.940800.92729

0.915410.904870.895450.886980.879300.872320.865930.860050.854640.849620.844960.840620.836560.832750.829180.825820.822640.81964

0.816800.814110.811550.809110.806790.804570.802460.800430.798490.796630.794840.793130.791480.789890.78836

0.78688

7.566072,776041.970411,645351.468571.356771.279291.22220

1.178261.143291.114741.090941.070761.053411.03831

1.025041.013261.002730.993260.984680.976870.969720.963160.957100.951480.946270.941410.936870.932610.928620.924850.921300.91794

0.914770,911750.908880.906160.903560.901080.898710.896440.894270,892190.890190.888270,88642

0.884640.88293

0.88128

8.364783.076322.187211.82837

1.633081.509461.423721.36051

1.311811.273041.241361.214951.192551.173281.156501.141751.128671.116971.106431.096891.088211.080261.072951.066211.059971.054171.048761.043711.038971.034521.030341.026381.02265

1.019111.015751.012561.009531.006631.003871.001240.998710.996290.993970.991750.989610.98755

0.985570.983660,98182

9.217303.397622.419562.02478

1,809811,673621,579101.50935

1,455591.412761.377751.348541.323761.302441.28388

1.267551,253061.240101.228431.217861.208231.199421.191331.183861.176941.170501.164511.158911.153651.148721.144071.139691.135551.131621.127901.124361.120991,117781.114721.111791,108991.106311.103731.101261.098891.09661

1.094411.092291.09025

9.812163.622232.582212.16241

1.933751.788821.688181.61388

1.556591.510931.473601.442451.416011.393251.37344

1,356001.340531.326691.314221.302941.292651.283241.274591.266601.259211.252341,245931.239941.234321.229051.224081.219401.214971.210771.206791.203011.199411.195981.192701.189571,186571.183701.180951.178311.175771.17333

1.170981.168721.16653

10.141853.746862.672532.238882.002641.852881.748851.67204

1,612801.565571.526951.494721.467361.443811,423301,40525

1.389231.374901.362001.350311.339661.329921.32096

1.312691.305031.297911.291271.285071.279251.273791.268651.263791.259201.254861.250731.24681

1.243081.239521.236131.232891.229781.226811.223961.221221,218591.21606

1.213631.211281.20902

11.165724.134492.953722.477152.217432.052691.938181.85358

1.788281,736201.693581.658001.62779

1.601771.57910

1.559151.541441,525591,511311.498381.486591.475811.465891.456731.448251.440371.433021.426141.419701.413651.407951.402571.397481.392671.388101.383751.379621.375681.371911.368321.364881.361581.358421.355391.352471.34967

1.346971.344361.34186

12.333174.577463.275542.750152.463742.281982.155572.062111.98993

1.932331.885171.845781.812311.783481.758361.73624

1.716591.699011.683161.668811.655721.643741.632731.622561.613141.604381.596211.588571.581411.574681.568351.562371.556711.551361,546271.541441.536841.532461.528271.524271,520451.516781.513261.509891.50664

1.503521.500521.497621.49483

13.724375.106513.660463.077032.758942.556972.416432.312462.23212

2.167962.115412.071492,034162.001981.973931.94922

1.927271.907621,889911.873861.859221,845821.833501.822121.811571.801761.79262

1.784061.776041.768511.761411.754711.74837

1.742371.736681.731261.726111.721191.716501.712021.707721.703611.699671.695891.692251.68875

1.685381.682131.67900

23

Page 30: Statistical Computation of Tolerance Limits

Table8. Two-sidedk (continued).

2

3456789

1011

1213

1416[17118

19120121!

22

2324252627282930313233343536373839404142

4344454647484950

24

P0.90

15.51241

5.788094.157093.499273.140582.912762.754142.636732.545942.47340

2.413952.36422

2.321942.285482.253672.225652.200742.178442.158332.140092.123472.108242.094232.081282.069292.058132.047732.038002.028872.020292.012212.004581.997371.990531.984041.977881.972001.966401.961061.955951.951061.94637

1.941881.937561.933421.929431.925581.921881.91831

Pr(Tv<_kg'fflKeg-ff}=y, y= 0.90

P0.95

18.220846.823284.91267

4.142473.722533.455743.269883.132233.025712.940542.870682.812222.76247

2.719552.682092.649062.619692.593382.569652.548122.528482.510482.493922.478622.464432.451232.438912.427392.416592.40643

2.396862.387822.379272.371162.363472.356162.349192.342552.336212.330152.324352.318792.313452.30833

2.303412.298672.294112.289712.28547

P0.9545

18.562346.954015.008184.223833.796193.524493.335213.195013.086522.999762.928602.869042.818352.774622.736452.702792.672862.646042.621862.599912.579892.561552.544662.529062.514602.501142.488592.476842.465822.455462.445702.436482.427772.419502.411662.404202.397102.390332.38386

2.377682.371762.366092.360652.355422.350402.345572.340922.336442.33211

P0.975

20.610977.739015.582054.712914.239103.938053.728283.572853.452533.35628

3.277313.211183.154893.106303.063873.026452.99316_.963332.936412.911982.889692.869262.850452.833072.816952.801952.787952.774852.762562.751012.740122.729842.720112.710882.702132.693802.685872.678312.671092.664192.65758

2.651242.645172.639332.633722.628322.623122.618112.61328

P0.99

23.423618.818636.372135.386774.849734.508504.270694.094453.957963.848753.759103.68400

3.620043.56481

3.516573.474013.436133.402173.371523.343703.318303.295023.273583.253763.235373.218263.202293.187343.173313.16012

3.147683.135933.124823.114283.104283.094763.085703.077053.068793.060903.053343.046093.03914

3.032463.026043.019873.013923.008183.00265

P0.9973

26.9579010.177587.367676.236525.620205.228634.955724.753434.596734,47129

4.368304.281994.208464.144944.089444.040453.996843.957723.922413.890343.861073.834223.809483.786623.765403.745643.727203.709933.693733.678483.664113.650533.637683.625503.613923.602923.592433.58242

3.572873.563733.554983.546593.538543.530803.523373.516213.509323.502673.49626

P0.999

29.36192

11.103088.046176.815976.145815.720075.423365.203395.032994.896574.78453

4.690634.610614.541484.481064.42772

4.380234.337634.299164.264224.232324.203054.176094.151164,128024.106484.08636

4.067524.049844.033214.017524.002713.988683.97538

3.962743.950723.939273.928343.917913.90792

3.898363.889203.880403.871953.863833.856013.848473.841213.83420

P0.9999

34.2947413.004249.440898.007647.227176.731456.385996.129875.931445.772555.642045.532625.439365.358775.288315.226095.170685.120965.076045.035244.997974.963784.932274.903124.876064.850874.827334.80529

4.784604.76513

4.746764.729414.712984.697394.682594.668504.655084.642274.630034.618324.607114.59636

4.586044.576124.566594.557414.548564.540044.53181

P P0.999937 0.99999

35.19027 38.5961213.34964 14.663769.69438 10.659088.22430 9.048947.42381 8.172396.91541 7.615766.56110 7.227886.29844 6.940326.09493 6.717525.93197 6.53911

5.79810 6.392545.68588 6.269655.59023 6.164905.50756 6.074355.43528 5.995185.37146 5.925265.31461 5.862975.26360 5.807075.21752 5.756575.17566 5.710685.13742 5.668775.10234 5.630305.07000 5.594845.04009 5.562045.01233 5.531594.98647 5.503224.96232 5.476734.93970 5.451914.91846 5.428614.89848 5.406674.87963 5.385984.86181 5.366434.84495 5.347924.82895 5.330354.81375 5.313664.79929 5.297784.78551 5.282654.77236 5.268214.75980 5.25441

4.74778 5.241204.73626 5.228564.72523 5.216434.71463 5.204794.70445 5.193604.69466 5.182844.68523 5.172484.67615 5.162504.66740 5.152884.65895 5.14359

|

Page 31: Statistical Computation of Tolerance Limits

Pn 0.50

2 13.651953 3.58453

2.287651.81188

6 1.565937 1.415268 1.313169 1.23916

10 1.18293

Table 9. Two-sided k.

Pr(Tv <klrfflKp1-_)= 7', 7'=0.95

P0.75

22.383005.937513.818403.040962.638412.391142.223042.100842.00770

P0.90

31.092578.305995.368094.290613.732583.389533.156042.986072.85631

P0.95

36.519629.788806.341105.076894.422164.019603.745513.545903.39343

P0.99

46.9449212.647178.220686.597995.757765.241114.889234.632844.43691

P0.999

58.8443115.9200510.376918.345307.293556.646896.206435.885455.64007

P0.9999

68.7290318.6440112.173549.802378.575027.820467.306526.931966.64561

P0.99999

77.3484921.0218713.7428911.075679.695248.846648.268677.847457.52540

Table 10. Two-sided k.

Pr{Tv < k1-_ l Kp l'_} = 7', 7'=0.99

234567i89

10

P P P P P P P P0.50 0.75 0.90 0.95 0.99 0.999 0.9999 0.99999

68.319378.121934.028552.823872.269571.953781.750151.607881.50274

112.0022413.434956.706184.724203.811683.291222.955082.719772.54553

155.5778018.782979.416286.655025.383264.657604.188663.860133.61664

182.7305022.1314011.118017.869846.373555.519644.967714.580944.29420

234.8908228.5865014.4056310.220248.291637.190776.479065.980195.61021

294.4267435.9783418.1777312.9206210.497529.114208.219737.592657.12749

343.8829242.1308521.3211615.1727912.3384010.720119.673648.939938.39562

387.0087847.5018424.0671617.1411013.9478012.1244810.9453610.118609.50523

25

Page 32: Statistical Computation of Tolerance Limits

Table 1 i. Comparison of approximate and exact results for two-sided tolerancefactor k for n = 2 and 10.

n=2 _'

0.90 0.95 0.99

p Approx. Exact Approx. Exact Approx. Exact

0.500.75

0.90

0.95

0.99

0.999

6.80958

11.40606

15.97787

18.79974

24.16655

30.22649

6.80826

11.16572

15.51241

18.22084

23.42361

29.36192

13.64602

22.85712

32.01879

37.67366

48.42846

60.57225

13.65195

22.38300

31.09257

36.51962

46.94492

58.84431

68.27314

114.35770

160.19493

188.48716

242.29504

303.05230

68.31937112.00224

155.57780

182.73050

234.89082

294.42674

P

0.50

0.75

0.90

0.95

0.99

0.999

n=10

Approx.

1.04151

1.77504

2.53516

3.01829

3.9593O

5.04563

0.90

Exact

1.05269

1.78828

2.54594

3.02571

3.95796

5.03299

Approx.

1.16612

1.98740

2.83846

3.379414.43299

5.64929

Exact

1.182932.00770

2.85631

3.393434.43691

5.64007

0.99

Approx.

1.47161

2.50805

3.58207

4.26472

5.594327.12926

Exact

1.50274

2.54553

3.61664

4.29420

5.610217.12749

Nonparametric Tolerance Limits

The nonparametrics (distribution-free) statistical analysis is applied to the one- and two-sidedtolerance limits to determine the level of dependency of the interval on the sample size at given proba-

bility and proportion of the population. The nonparametrics analysis assumes a continuous distribution,

but it precludes any requirement for assumptions, regarding the distribution of data. The data from tables

1 through 10 cannot be applied to the nonparametrics analysis.

One-sided tolerance limits pertain to the relative effect of the proportion: at least a prOportion P

of the population is greater than X (r) or less than x(n-l-m) with probability y. In a comparison, two-sidedtolerance limits primarily concern the interval within which at least a proportion P of the population

occurs. A typical problem embraces a question of how large the sample size n should be so that at least a

proportion P of the population is between A"(r) and x(n-l-_) with probability yor more. One interpretationof this nonparametrics problem demonstrates a situation, for example, where one has a sample of nevents and determines to know how large sample size n can be obtained if one has attained a confidence

level of 90 percent that at least 80 percent of the population lies between x_ 1) and xO,), the smallest and

largest events in one's sample.

26

Page 33: Statistical Computation of Tolerance Limits

Therandomsamplevalues,whicharearrangedin orderof increasingmagnitude,arerepresentedasxo), x(2), x(3) ..... x_,) from a distribution having a density functionf(x) and distribution function F(x).

The order statistics X(r) and x(s) consist of the nonparametric tolerance limits. Let x be a continuous ran-

dom variable and one calculates the lower limit L and upper limit U. Accordingly, the probability thatthe value of the random variable falls between L and U is established as

(41)

where f(x) is the unknown continuous probability density function of the random variable x. L and U will

be defined to be 100 P percent tolerance limits at probability _.

Letting L = X(r) (lower tolerance limit) and U = x(s) (upper tolerance limit) take place in equation

(41), the resulting expression becomes

Pr(fX(s) f(x)dx>P}=y'[Jx(r)(42)

Defining

gt

F(t) = J_ f(x)dx ,

it follows that equation (42) is now rewritten as

Pr_.F(xs)-F(xr)] >--P} = Y. (43)

A random sample xl, x2, x3 ..... Xn of size n is obtained from a cumulative distribution function

F(x), and their distribution is defined by

dB = dF(xl) dF(x2) dF(x3) ... dF(xn) (44)

Hence, a transformation is made to perform integration for

= f xr dE(t) = F(xr) . (45)Zr

The distribution of Zr is derived from a beta distribution of the first kind given by

n!dW = (r-1)!(n-r)! zr-a(1-Zr)_-rdzr ' 0 < Zr < 1 . (46)

ThUS, considering next a distribution for the rth order statistic Xr, one puts F(xr) = Zr to obtain the follow-

ing expression:

n! {F(xr)} r-1 (1-F(xr)} nr f(xr)dx r (47)dW - (r-l)!(n-r)[

27

Page 34: Statistical Computation of Tolerance Limits

Sincethesamplesof sizen constitute any distribution F(x) with a continuous probability density func-

tion fix), the sampling distribution of F(xr) yields

where

dW = (S(Xr)) r-I (1-e(Xr)) n-r dF(xr)

B(r,n-r+l)

n!B(r,n-r+ 1) - (r- 1) !(n-r) ! '

from the gamma function. If Xr and xs are independent and continuous, then the joint distribution for

F(xr) and F(xs), r < s, is given by

NV-" (F(xr))r-I (F(xs)-F(xr)}S'-r-' (1-F(xs))n-'s dF(xr) dF(xs)B(r,s-r)B(s,n-s+ l )

New variables of the transformation y,z can be introduced by setting

y = F(xs)-F(x r) , z = F(xr) •

Furthermore, the Jacobian is obtained

_)y _y

_z _z

0s _r

1 -1[--" "-- 1 °

0 1

(48)

(49)

(50)

Then, by the change of variable formula,

f ,z y,z)=f,f y,z)IJI, (51)

is obtained. The bars I I denote absolute value.

The process from equation (51) yields the following result

Z r-lys-r-l(1-y--z) n-_'dydz (52)dVy 'z = B(r,s-r) B(s,n-s+l)

When the joint distribution of two random variables is given, one needs to obtain the distribution of one

of the variables alone. Thus, equation (52) is integrated out the variable z over its range (0, l-y), obtain-

ing for the marginal distribution of y

s-r-I fOy.. dy l-y

dVr's = B(r,s-r) B(s,n-s+l) zr-l(1-y-z)_-Sdz . (53)

28

Page 35: Statistical Computation of Tolerance Limits

Useof z = (1-y)t reduces equation (53) to

dVr_ $ Ys-r-l(1-Y)n'4+rdy fo 1B(r,s-r) B(s,n-s+ l ) tr-l(1-t)'_dt =

dvrs' = B(s-r,n-s+r+l)

y s-r-1(l-y) n-4+rdy B(r, n-s+ 1)B(r,s-r)B(s,n-s+ l )

, 0_y_l

(54)

Thus, y = F(xs)-F(xr) is distributed as a beta variate of the first kind with parameters depending only on

the difference (s-r).

Using equation (54), equation (53) becomes

Pr{y > P} = Ys-r-l(1-Y)n-_+rdYB(s-r,n-s+r+ 1) = Y "

(55)

Equation (55) is rewritten in terms of the incomplete beta function as

Pr {F(xs)-F(x _) > P} = 1-lp(s-r,n-s+r+l) = 7 • (56)

Equation (56) provides the nonparametric tolerance interval (Xr, Xs) and related parameters such as the

minimum proportion P of F(x), the probability 7, the sample size n and the order statistics' positions rand s.

Equation (56) is equivalent to another equation, namely,

7>r._, (7) (l_p)_p_ , (57)

where the sample size n depends on the solution for both types of one-sided tolerance limits and for the

two-sided tolerance limits. (7) is the binomial coefficient, defined as

(7)- °'i!(n-i) !

The data for nonparametric tolerance limits computed from equation (56) are tabulated in table

12. The numerical data have shown that the sample number of at least 230 items would be required if the

acceptance criteria without any failure are satisfied for 99-percent proportion at 90-percent confidencelevel. Should a single failure occur, then a sample of 388 items would be obtained. The sample of atleast 3,000 items is based on achievement of 23 failures.

29

Page 36: Statistical Computation of Tolerance Limits

Table 12. Nonparametrictolerancelimits.

0.50

0.75

0.90

0.95

0.99

Notes:

P

0.50

0.75

0.90

0.95

0.99

0.50

0.75

0.90

0.95

0.99

0.50

0.750.90

0.95

0.99

0.500.75

0.90

0.95

0.99

0.50

0.75

0.90

0.95

0.99

No Failure

r n

1 21 3

1 7

1 14

1 69

1 3

1 5

1 14

1 28

1 138

1 4

1 91 22

1 45

1 230

1 5

1 111 29

1 59

1 299

1 7

1 17

1 44

1 9O

1 459

One Failure

i-

2

22

2

2

2

2

2

2

2

2

2

2

2

2

2

2

22

2

2

2

2

2

2

4

7

17

34

168

510

27

54

269

7

15

3877

388

8

18

46

94

473

11

24

64

130

662

c_ = confidence level

P = proportionFailure to meet acceptance criteria.

Two Failures

3

3

3

3

3

3

3

3

3

3

3

3

3

3

3

3

3

33

3

3

33

3

3

n

6

11

27

54

268

7

1539

78

392

9

20

52

105

531

11

24

61

124

628

14

31

81

165

838

Three Failures

F

8

15

37

74

367

10

20

51

102

510

12

25

65

132

667

1429

76

153

773

17

37

97

198

1,001

(r-l) Failures

r n

4

44

4

4

4

4

4

4

4

4

4

4

4

4

4

4

44

4

4

44

4

4

1,500751300

151

31

1,481734

289

143

27

1,463720

280

135

24

1,453711

274

13122

1.433

695263

124

19

3,000

3,000

3,000

3,000

3,000

3,000

3,000

3,000

3,000

3,000

3,000

3,000

3,000

3,000

3,000

3,0003,000

3,000

3,000

3,000

3,000

3,000

3,000

3,000

3,000

CONCLUSIONS

The four computer codes have been written to implement the algorithms to calculate the parame-ters for the exact tolerance factor k's for derivation of the one- and two-sided statistical tolerance limits,

using the new theory. One resulting conclusion from this study has shown that the computer codes can

perform faster and more efficiently. The exact data, based on normal distributions, have demonstrated

that the approximation is somewhat satisfactory for even small sample sizes.

30

Page 37: Statistical Computation of Tolerance Limits

APPENDIX A

Derivation of Chi Distribution

Chi-square probability function (tail area) is constructed in the form of

1 ft?v fi- _e-½drQ[w(z)]= _ x2 '

_(_)where v denotes degrees of freedom and F(-) is the gamma function

(fo )Let t = vx 2 and dt = 2 vxdx.

Substituting the preceding equations into equation (A1) gives

v_ 1

1 fx_ (VX2)-_Q[w(z)] = ._ v_2

_(_)

v._2

_..12_.e 2vxdr .

After manipulation, equation (A2) becomes

VX 2_(_)_x v-1 e dxQ_w_l-_,_ _

For the reason of symmetry based on addition of integration area, the final expression is given by

4(_)_ _x_Q[w(z)] = x v-I e dr .

Equation (A4) is the chi distribution.

(A1)

(A2)

(A3)

(A4)

31

Page 38: Statistical Computation of Tolerance Limits

APPENDIX B1

One-Sided Ke:-

Standardized normal random variable exceeded with probability p

Proportion K t,

0.99999

0.99996832876

0.9999

0.999

0.998650102

0.9975

0.996

0.99

0.97724987

4.2648907939

4.0000000000

3.71901648553.0902323062

3.0000000000

2.8070337684

2.6520698079

2.3263478743

2.0000000000

0.975

0.96

0.95

0.9350.90"

0.85

0.84134477

1.9599640498

1.7506860747

1.64485362781.5141018878

1.2815515655

1.0364333895

1.0000000000

0.80

0.75

0.700.65

0.60

0.55

0.50

0.8416212336

0.6744897502

0.5244005127

0.3853204664

0.2533471031

0.1256613469

0

32

Page 39: Statistical Computation of Tolerance Limits

APPENDIX B2

Two-Sided Kp

Standardized normal random variable exceeded with probability p

Proportion Kp

0.99999

0.99993665752

0.9999

0.999

0.997300204

0.99

0.975

0.95449974

4.4171734135

4.0000000000

3.8905918864

3.2905267315

3.0000000000

2.5758293036

2.2414027281

2.0000000000

0.950.90

0.85

0.80

0.75

0.70

0.6826894925

1.9599640498

1.64485362781.4395314711

1.2815515655

1.1503493804

1.0364333895

1.0000000000

0.65

0.60

0.55

0.50

0.450.40

0.35

0.30

0.25

0.200.15

0.10

0.05

0

0.9345892911

0.8416212336

0.7554150264

0.6744897502

0.5977601260

0.5244005127

0.4537621902

0.3853204664

0.3186393640

0.2533471031

0.18911842630.1256613469

0.0627067779

0

33

Page 40: Statistical Computation of Tolerance Limits

APPENDIX C1

Simulation Code, One-Sided k

'K1-FACTORDEFDBL A-Z

INPUT"SAMPLE SIZE=";NSINPUT "PROPORTION";PINPUT "CONFIDENCE=";CLSTART=TIMERPI=3.141592654#'INVERSE NORMALQ=I-P:T=SQR(-2*LOG(Q))AO=2.30753:A1=.27061:B1=.99229:B2=.04481N U=A0+AI*T:DE= I+B 1*T+B2*T*TX=T-NU/DE =L0: Z=I/SQR(2*PI)*EXP(-X*X/2):IF X>2 GOTO L3V=25-13*X*XFOR N=I 1 TO 0 STEP-1U=(2*N+I)+(-1)^(N+I)*(N+I)*X*XJVV=U:NEXT NF=.5-Z*XNW=Q-F:GOTO L2L3:V=X+30FOR N=29 TO 1 STEP-1U=X+NNV=U :NEXT NF=Z/V :W=Q-F :GOTO L2L2:L=L+IR=X:X=X-W/Z

E=ABS(R-X)IF E>.00001 GOTO L0'END OF INVERSE NORMAL

'CALCULATION OF FACTORIALN=NS:NU=N-1MT=INT(NU/2):UT=NU-2*MTGT=IFOR I= 1 TO MT- I+UTKT=IIF UT=0 GOTO L1KT=I-.5L1 :GT=GT*KTNEXT IGT=GT* (1+UT*(SQ R(PI)- 1))G F=GT*2^(N U/2-1 )'END OF FACTORIAL

34

Page 41: Statistical Computation of Tolerance Limits

'SECANT METHODKP=X:J=I :K=KPK0=K:GOSUB INTEGRATION:SF0=SF

K=K*(1 +.0001 ):KI=K: GOSUB INTEGRATION:SF1 =SFBEGIN:K=K1-SFI*(K1-K0)/(SF1-SF0)IF ABS((K1-K)/K1)<.000001 GOTO RESULTJ=J+I:K0=KI:KI=K:SF0=SF1GOSUB INTEGRATION:SFI=SF:GOTO BEGINRESULT:FINISH=TIMERBEEP:BEEPPRINT K

PRINT "K";"(";J;") =";USING"##.####";KPRINT "TIME=";FINISH-START;"SECONDS"'END OF SECANT METHODWHILE INKEY$--"":WEND

'SIMPSONINTEG RATION:L1=0: L2= 10IF N>40 THEN L2=20

DL=KP*SQR(N):TP=K*SQR(N)Y=NU/2

M=2:E=0:H=(L2-L1)/2X=LI:GOSUB FUNCTIONY0=Y:X=L2:GOSUB FUNCTIONYN=Y:X=LI+H:GOSUB FUNCTION

U=Y:S=(Y0+YN+4*U)*H/3START:M=2*MD=S:H=H/2:E=E+U:U=0FOR I-1 TO M/2

X=L1 +H*(2*I-1):GOSUB FUNCTIONU=U+YNEXT I

S=(Y0+YN+4*U+2*E)*H/3IF ABS((S-D)/D)>.00001# GOTO STARTSF=S/GF-CLRETURN'END OF SIMPSON

FUNCTION: Z=TP*X/SOR(NU)-DLT0=Z:G0= 1/SQR(2*PI)*EXP(-Z*Z/2)A1 =.3193815: A2=-.3565638: A3= 1.781478:A4=- 1.821256:A5= 1.330274IF Z<0 THEN T0=-ZW= 1/(1 +.231649"T0)P1 = ((((A5*W+A4)*W+A3)*W+A2)*W+A 1)*WPH=I-G0*P1IF Z<0 THEN PH=I-PH

Y= PH*X^(N U- 1)* EXP(-X*X/2)RETURN

3S

Page 42: Statistical Computation of Tolerance Limits

APPENDIX C2

Simulation Code, Two-Sided k

'K2-FACTORSTART:DEFDBL A-ZPI=3.141592654#

INPUT"SAMPLE SIZE=";NINPUT"PROPORTION=";PINPUT"CONFIDENCE=";CLSTART=TIMER

NU=N-1 :X=(NU+2)/2DEF FN HTN(X)=(EXP(X)-EXP(-X))/(EXP (X)+EXP(-X))CALL GAMMACALL NORMIN

PRINT"KP=";KP'SECANT METHODK=KP:J=IK0=K:GOSUB INTEGRATION:SF0=SFK=K*(l+.0001):K1 =K:GOSU B INTEGRATION:SFI=SFBEG IN:K=K1 -SF 1*(K1 -K0)/(SF 1-S F0)IF ABS((K1-K)/K1)<.000001 GOTO RESULTJ=J+l :K0=K1 :K1 =K:SF0=SF 1GOSUB INTEGRATION:SFI=SF:GOTO BEGINRESULT:FINISH=TIMERBEEP'BEEPPRINT KPRINT" "'" "- -" " " "K, ( ,J, ) = ;USING ##.#### ;KPRINT "TIM E=";FINISH-START;"SECONDS"'END OF SECANT METHODWHILE INKEY$="":WENDGOTO START

'START SIMPSONINTEGRATION:A=0:B=5:M=32H=(B-A)/2/MFE=0:FU=0

X=A:W=KP/K:UC=K/SOR(N):HC=H/K/SQR (N)CALL FUNCTION:FA=FFOR I-1 TO 2"M-1CALL RUNGEX=A+I*HCALL FUNCTIONU=l MOD 2IF U=0 THEN FE=FE+F ELSE FU=FU+F

36

Page 43: Statistical Computation of Tolerance Limits

NEXT ICALL RUNGEX=B:CALL FUNCTION:FB=FS=H*(FA+2*FE+4*FU+FB)/3SF=2*S-CLRETURN

SUB RUNGE STATICSHARED HC,UC,W,H,X'RUNGE-KUTTA/3

XI=X:WI=W:U=X*W*UC:KI=HC*FNHTN(U)X=XI+H/2:W=WI+K1/2:U=X*W*UC:K2=HC*FNHTN(U)X=XI+H:W=W1-KI+2*K2:U=X*W*UC:K3=HC*FNHTN(U)W=W1+(K1+4*K2+K3)/6END SUB

SUB FUNCTION STATICSHARED PI,NU, GNU,F,W,X'CHI-SQUAREWL=NU*W*W

C=(WL/2)^(NU/2)*EXP(-WI_/2)/GNUQ=I :J=0:S=0LINE2: J=J+I:D=NU+2*JR=WL/D:Q=Q*R:S=S+QIF Q>.000001 GOTO LINE2

P=(I+S)*C'END CHI-SQUARE

F=(1-P)*EXP(-X*X/2)/SQR(2*PI)END SUB

SUB GAMMA STATICSHARED X,PI,GNUZ=X+4:IF X>4 THEN Z=X

G=SQR (2*PI/Z)*EXP(Z*LOG(Z)-Z+ 1/12/Z-1/360/Z^3+ 1/1260/Z^5 - 1/1680/'Z^7+ 1 /1188/Z^9)IF X>4 GOTO L1G=G/X/(X+I)/(X+2)/(X+3)LI:GNU=GEND SUB

SUB NORMIN STATIC

SHARED KP,P,PIQ=(1-P)/2:T=SQR(-2*LOG(Q))A0=2.30753:A1 =.27061 :B1 =.99229:B2=.04481NU=A0+A 1*T: D E= 1+ B 1*T+B2*T*TX=T-NU/DE

3?

Page 44: Statistical Computation of Tolerance Limits

LO: Z=I/SQR(2*PI)*EXP(-X*X/2):IF X>2 GOTO L3V=25-13*X*XFOR N=I 1 TO 0 STEP-1U=(2*N+I)+(-1)A(N+I)*(N+I)*X*X/VV=U:NEXT NF=.5-Z*X/VW=Q-F:GOTO L2L3:V=X+30FOR N=29 TO 1 STEP-1U=X+NNV=U :NEXT NF=ZN :W=Q-F :GOTO L2L2:L=L+IR=X:X=X-W/ZE=ABS(R-X)IF E>.000001 GOTO LOKP=XEND SUB

38

Page 45: Statistical Computation of Tolerance Limits

REFERENCES

It

.

.

,

.

.

Abramowitz, M., and Stegun, I.A.: "Handbook of Mathematical Functions." Dover Publications,Inc., New York, NY, 1965.

Conover, W.J.: "Practical Nonparametric Statistics." Second Edition, John Wiley and Sons, NewYork, NY, 1980.

Guttman, I.: "Statistical Tolerance Regions: Classical and Bayesian." Hafner Publishing Company,Darien, CN, 1970.

Kendall, M., and Stuart, A.: "The Advanced Theory of Statistics." Vols. I and II, Macmillan

Publishing Company, Inc., New York, NY, 1977.

Owen, D.B.: "A Special Case of a Bivariate Noncentral t-Distribution." Biometrika, vol. 52, Nos. 3

and 4, 1965, pp. 437-446.

Webb, S.R., and Friedman, H.A.: "Exact Two-Sided Tolerance Limits Under Normal Theory."

Rocketdyne, a Division of North America Rockwell Corporation, report NAR 54416, 1968.

39

Page 46: Statistical Computation of Tolerance Limits

APPROVAL

STATISTICAL COMPUTATION OF TOLERANCE LIMITS

By J.T. Wheeler

The information in this report has been reviewed for technical content. Review of any informa-

tion concerning Department of Defense or nuclear energy activities or programs has been made by the

MSFC Security Classification Officer. This report, in its entirety, has been determined to be unclassified.

J.C.

Director, Structures and Dynamics Laboratory

"_" U.S, GOVERNMENT PRINTING OFFICE 1993--533-108/80127

r=

=-.=

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Page 47: Statistical Computation of Tolerance Limits

Form Approved

REPORT DOCUMENTATION PAGE OMBNo. 0704-0188

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1. AGENCY USE ONLY (Leave blank) | 2, REPORT DATE 3. REPORT TYPE AND DATES COVERED

I October 1993 Technical Memorandum

4. TITLE AND SUBTITLE S. FUNDING NUMBERS

Statistical Computation of Tolerance Limits

6. AUTHOR(S)

J.T. Wheeler

7. PERFORMINGORGANIZATIONNAME(S)AND ADDRESS(ES)

George C. Marshall Space Flight Center

Marshall Space Flight Center, Alabama 35812

9. SPONSORING/MONITORINGAGENCYNAME(S)AND ADDRESS(ES)

National Aeronautics and Space Administration

Washington, DC 20546

8. PERFORMING ORGANIZATIONREPORT NUMBER

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AGENCY REPORT NUMBER

NASA TM-I08424

11. SUPPLEMENTARYNOTES

Prepared by Structures and Dynamics Laboratory, Science and Engineenng Directorate

12a.DISTRIBUTION/AVAILABILITYSTATEMENT

Unclas sifted--Unlimited

12b. DISTRIBUTION CODE

13. ABSTRACT (Maximum 200words)

Based on a new theory, two computer codes have been developed specifically to calculate theexact statistical tolerance limits for normal distributions within unknown means and variances for the

one-sided and two-sided cases for the tolerance factor, k. The quantity k is defined equivalently in terms

of the noncentral t-distribution by the probability equation. Two of the four mathematical methods

employ the theory developed for the numerical simulation. Several algorithms for numerically integrat-

ing and iteratively root-solving the working equations are written to augment the program simulation.

The program codes generate some tables of k's associated with the varying values of the proportion and

sample size for each given probability to show accuracy obtained for small sample sizes.

14. SUBJECTTERMSstatistics, probability, life-testing, process control, reliability,

nonparametrics, stochastic process, tolerance limits, numerical statistics,

quality control, tolerance factors17. SECURITY CLASSIFICATION 18. SECURITY CLASSIFICATION 19. SECURITY CLASSIFICATION

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