Chapter 9: Inference for Categorical Data

Inference for Categorical Data

525

CHAPTER OUTLINE

9.1 Inference for Two-Way Tables
9.2 Goodness of Fit

Introduction

We continue our study of methods for analyzing categorical data in this chapter. Inference about proportions in one-sample and two-sample settings was the focus of Chapter 8. We now study how to compare two or more populations when the response variable has two or more categories and how to test whether two categorical variables are independent. A single statistical test handles both of these cases.

The first section of this chapter gives the basics of statistical inference that are appropriate in this setting. A goodness-of-fit test is presented in the second section. The methods in this chapter answer questions such as:

• Are men and women equally likely to suffer lingering fear symptoms after watching scary movies like 10 Cloverfield Lane and The Boy at a young age?
• Is there an association between texting while driving and automobile accidents?
• Does political preference predict whether a person makes contributions online?