The TTEST Procedure

The WEIGHT statement weights each observation in the input data set by the value of the WEIGHT variable. The values of the WEIGHT variable can be nonintegral, and they are not truncated. Observations with negative, zero, or missing values for the WEIGHT variable are not used in the analyses. Each observation is assigned a weight of 1 when the WEIGHT statement is not used. The WEIGHT statement cannot be used with an input data set of summary statistics.