You can use the **Variables** tab to specify the variables for the Linear Regression analysis.

The **Variables** tab is shown in FigureĀ 21.6. The Y variable is the response variable. The dialog box supports multiple X (explanatory) variables. All X and Y variables
must be interval variables.

The Linear Regression analysis does not support nominal classification variables, nor does it support specifying interaction
effects such as `X1`

*`X2`

or higher-order polynomial effects such as `X1`

. You can create models with these features by using the Generalized Linear Models analysis, as described in ChapterĀ 24: Model Fitting: Generalized Linear Models.