ABSTRACT
This chapter introduces common statistical techniques of cross tabulations, comparison of means, and measures of association that are used to create comparison groups, control for rival explanations, and determine the strength of relationships between variables. There are many different measures of association but the chapter focuses on the most common ones used with nominal, ordinal, and interval or ratio data. Analysts can use a variety of measures of association to determine the strength of any apparent cause-and-effect or impact relationship. A control variable is another variable that is applied to the statistical analysis to determine whether it changes the original relationship between the independent and dependent variables. Suppose a public university's admissions committee is trying to determine if there is a relationship between how well students do in high school and their performance in college. The best measure of academic performance, in the committee's opinion, is the grade point average (GPA).
