IN THIS CHAPTER
Working with two variables
Working with replications
Mixing variable types
Working with multiple dependent variables
In Chapter 11, I show you how to test hypotheses with two samples. In Chapter 12, I show you how to test hypotheses when you have more than two samples. The common thread in both chapters is one independent variable (also called a factor).
Many times, you have to test the effects of more than one factor. In this chapter, I show how to analyze two factors within the same set of data. Several types of situations are possible, and I describe R functions that deal with each one.
Imagine that a company has two methods of presenting its training information: One is via a person who presents the information orally, and the other is via a text document. Imagine also that the information is presented in either a humorous way or a technical way. I refer to the first factor ...