ABSTRACT
Chapter 13 discusses methods for evaluating relationships between variables. It begins with information on constructing contingency tables and using percents calculated on data in the tables to assess relationships. The chapter continues on to the discussion of several measures of association. Contingency tables for two- and three-variable relationships are discussed and illustrated. Measures of association primarily provide a gauge of the strength of association between two variables. Many also indicate the direction of the relationship—positive or negative. Measures of association for variables of each level—nominal, ordinal, or interval—are discussed and illustrated. We emphasize the importance of using a measure of association appropriate to the measurement level of the variables involved. Control variables are third variables added to the analysis of a two-variable relationship. Their use to determine if they impact the original relationship is discussed and illustrated. The chapter explains the different changes in two-variable relationships that can occur with the addition of control variables.
