CONTENTS

Table of Contents
Introduction

1. Descriptive Statistics in Evaluation
2. Subgroup Analysis
3. Variable - Are They Related?
4. Correlation
5. The t-Test of Difference Between Means

Supplements
Resources
Glossary

Wading Through the Data Swamp:
Program Evaluation 201

The t-Test of Differences Between Means:
Independent Samples t-Test for Posttest Data

Step 3: Determine the difference in means between the two groups.

Subtract the mean for the comparison group from the mean for the participants. The result of the subtraction is -1.18 (2.32 - 3.5).