The REG Procedure

VAR Statement

VAR variables ;

The VAR statement is used to include numeric variables in the crossproducts matrix that are not specified in the first MODEL statement.

Variables not listed in MODEL statements before the first RUN statement must be listed in the VAR statement if you want the ability to add them interactively to the model with an ADD statement, to include them in a new MODEL statement, or to plot them in a scatter plot with the PLOT statement.

In addition, if you want to use options in the PROC REG statement and do not want to fit a model to the data (with a MODEL statement), you must use a VAR statement.