You can use the Roles tab to specify a frequency variable or weight variable for the analysis. (See Figure 24.18.) You can also specify an offset variable.
A frequency variable is a numeric variable whose value represents the frequency of the observation. If you use a frequency variable, the underlying procedure assumes that each observation represents n observations, where n is the value of the frequency variable.
A weight variable is a numeric variable with values that are relative weights for a weighted regression.
An offset variable is a variable used as a vector of constants in the regression. Its regression coefficient is set to 1. This corresponds to the OFFSET= option in the MODEL statement.