The TTEST Procedure

The pair-lists in the PAIRED statement identifies the variables to be compared in paired comparisons. You can use one or more pair-lists. Variables or lists of variables are separated by an asterisk (*) or a colon (:). The asterisk requests comparisons between each variable on the left with each variable on the right. The colon requests comparisons between the first variable on the left and the first on the right, the second on the left and the second on the right, and so forth. The number of variables on the left must equal the number on the right when the colon is used. The differences are calculated by taking the variable on the left minus the variable on the right for both the asterisk and colon. A pair formed by a variable with itself is ignored. Use the PAIRED statement only for paired comparisons. The CLASS and VAR statements cannot be used with the PAIRED statement.

Examples of the use of the asterisk and the colon are shown in Table 99.4.