1. Guide to Using Excel For Basic Statistical Applications
To Accompany
Business Statistics: A Decision Making Approach, 7th Ed.
Chapter 11:
Hypothesis Tests and Estimation for Population Variances By
Groebner, Shannon, Fry, & Smith
Prentice-Hall Publishing Company
Copyright, 2008

2. Chapter 11 Excel Examples
Testing Two Variances -
Bank ATM Machines

3. Testing-Two Variances - Bank ATM Machines
Issue: System programmers believe that the original ATM computer program will result in a higher standard deviation in transaction times than the new program
Objective: Use Excel 2007 to help test a hypothesis about the standard deviation of two groups.
Data file is ATM.xls

4. Testing-Two Variances - Bank ATM Machines
Open the file ATM.xls

5. Testing-Two Variances - Bank ATM Machines
Select the Data tab
Select Data Analysis
Select F-Test Two sample for Variances OK

6. Testing-Two Variances - Bank ATM Machines
Set Variable 1 Range to A1:A8
Set Variable 2 Range to B1:B12
Select Labels
Set alpha value to 0.01
Set Output range to D1 OK

7. Testing-Two Variances - Bank ATM Machines
Since F = > F critical = 5.39, reject Ho and conclude that the variance for Original Software exceeds that for the new system