We use ”contingency tables” to link two or more categorical variables together.

For instance, in the Accu-Phi case study you may wish to associate license and size. This analysis would tell you the number and percentage of premium versus freeware users in different size bands of customer. Figure 15.2 Crosstab example of relating two categorical variables shows an example of this analysis, which is widely called “crosstabs.”

In contingency tables, each unique combination of categories is called a “cell.” For instance, the combination of Small and Freeware customers would be a cell.

SAS generates contingency tables using the PROC FREQ procedure. To see an example of a contingency table in our data, in which we want to link the ordinal variable Size to the categorical variable License, open and run the file “Code08c Categ association crosstabs.” You will get tables and charts comparing and associating the categories, like Figure 15.2 Crosstab example of relating two categorical variables above, although with a little more detail.