Data MiningSupplemental Resources on Class

Website

Concept Map

Data Mining

Big Data

Implementation

Isolate Assumption

s

Design: Accurac

y

3-D Reference

s

Sum, Average, Min, Max,

Count, RandBetween

Paste Special

Mixed Cell Reference

s

Objectives

▪Explain the Accuracy principle of Spreadsheet Design

▪Demonstrate Excel features that support basic data mining.

▪Formula ▪ created by you▪= A1 + A10

▪Function ▪keyword defined by Microsoft▪=SUM(A1:D1)▪Functions are more flexible than formulas

Formula vs. Function

Different Results

=B3+B4+B5+B6

=SUM(C3:C6)

If you delete Row 5=SUM(C3:C5)

▪SUM

▪AVERAGE

▪MIN and MAX

▪COUNT

Common Functions

Cell Address Reference Changes when Copied

A1 Relative Vertically or Horizontally

$A$1 Absolute Never

$A1 Mixed Vertically

A$1 Mixed Horizontally

Relative, Absolute & Mixed Cell References

Vertical Copy

Vertical vs. Horizontal Copy

▪ Is the formula entered going to be copied?

▪ If so, which direction?

▪ If it’s copied vertically, do you want the row references to change? If it’s copied horizontally, do you want the column references to change?

▪Do you want such a change to take place?

Cell Reference Decisions

Cell Reference Decisions

CopyFormula?

Vertical orHorizontal?

ChangeRows?

ChangeColumns?

Yes

No Stop

HorizontalVertical

YesYes

Stop

No

Enter $ beforecolumn letters

that shouldnot change

No

Enter $ beforerow numbers that shouldnot change

Start

http://www.lacoste.pamplin.vt.edu/web1504/resources/video/ss.html

1. Will you copy this function?

2. If so, which direction: vertical or horizontal?

3. If you copy vertically, Excel will automatically change all relative row references. Do you want those row references to change?

Cell Reference Example #1

=SUM(B2:D2)

Cell Reference Example #2

▪Which calculation needs a mixed cell reference?

▪Where should the $ go?

▪Know the order of operations.

▪Select the correct function or construct the correct formula. (Choose a function over a formula.)

▪ Isolate assumptions.

▪Check relative and absolute cell references.

▪Double-check all calculations.

Spreadsheet Design: Accuracy

▪Store numbers in cells

▪Write equations to point to cells containing numbers

Isolate Assumptions

Isolate Assumption Example

Assumption

=E2+3 is incorrect=E2+H2 is correct

Generate Data with RANDBETWEEN

▪= RANDBETWEEN(low, high)

Paste Special - Values

http://www.lacoste.pamplin.vt.edu/web1504/resources/video/ss.html

MAC: Edit Menu, Paste Special

3-D Reference

▪Cell reference that refers to a cell on a different worksheet

▪Function is on Sheet 1▪Summing cell A1 on Sheets 2 thru 13

=SUM(‘Sheet 2:Sheet 13’!A1)