Answers to Review WS (2-5)P. 503 #10

Review for Ch 19 & 20 TEST

WS #2

• Assumptions are met.

* (1 )p pME z

n

.83(.17)1.645 .0618

100ME

WS #3

* (1 )p pME z

n

.35(.65).03 1.96

972n

n

Notes: Always round up when reporting n.In this problem we had some idea what p should be. Many times we do not. If we don’t know then use 0.5 for p.

WS #4

ˆ.71

(1 )

.2386

p pz

p pn

p

: .45

: .45o

a

H p

H p

Fail to reject the null since p-value is greater than alpha = .05. There is no evidence to suggest that the proportion of freshmen placed on academic probabation is less than 45%.

p is proportion of freshmen placed on academic probation.

Assumptions are all met – be sure to write formulas and plug in values to check.

Be sure to write formula!

WS #5

• Assumptions not met. Sample size is too small for np>10