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 5: Square the sum of the scores for both groups.

This step is straightforward. All we have to do is square the sums that were done in step 4. The square of the sum of participants' scores is 13,456 (116 × 116). The square of the sum of comparison group's scores is 30,625 (175 × 175). You will use these numbers in step 7, the sum of squares calculation.