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

Distribution Shapes

Before we begin discussing descriptive statistics, let's learn about distribution shapes.

• Normal or symmetrical distributions
• Skewed distributions
• Positively skewed distributions
• Negatively skewed distributions
• Bimodal distributions
• Uniform distributions

Distribution Shapes Applet

This applet will allow you to visualize the difference between distributions. Several types of distributions are possible.

Instructions: Use the menu at the bottom of the graph to select different distributions shapes.

X = Days Used in the Past 30 Days
Y = Number of Participants

This applet from Seeing Statistics™ is used under license. Any reproduction or other use is strictly prohibited.