1. Guide to Using Excel For Basic Statistical Applications
To Accompany
Business Statistics: A Decision Making Approach, 6th Ed.
Chapter 10:
Hypothesis Tests for One and Two Variances By
Groebner, Shannon, Fry, & Smith
Prentice-Hall Publishing Company
Copyright, 2005

2. Chapter 9 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 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 File ATM.xls

5. Testing-Two Variances - Bank ATM Machines
Click on Tools, then Data Analysis and finally on F-Test for Two Sample Variances

6. Testing-Two Variances - Bank ATM Machines
Supply Variable Ranges, Significance Level, and Output Range
Click on OK.

7. Testing-Two Variances - Bank ATM Machines
Since F = > F critical = 5.38, reject Ho and conclude that the variance for Original Software exceeds that for the new system