Chapter 8 Moderation

In this tutorial, we will learn to examine bivariate relationships to understand if it depends on a third variable. Put differently, does the relationship differ for population subgroups? This is known as moderation (or statistical interaction).

In statistics, moderation occurs when the relationship between two variables depends on a third variable. In this case, the third variable is referred to as the moderating variable or simply the moderator. The effect of a moderating variable is often characterized statistically as an interaction; that is, a third variable that affects the direction or strength of the relation between your explanatory and response variable.

We will build on one example in Chapter 7 to examine how to look at moderation for ANOVA, chi-square, and correlation.