ABSTRACT
One of the primary goals of analytic methods is to understand the relationships between variables. For instance, we might be interested in the relationship between player performance and team performance or in the relationship between performance in a given year and performance in the following year. In this chapter, several different approaches for measuring the strength of the relationship between variables are presented; these measures reduce the properties of such a relationship to a single number that is useful as a simple summary of the relationship between variables. In Chapter 6, we go a step further and consider mathematical models for these relationships.
