BY variables ;

A BY statement can be used with the SIMNORMAL procedure to obtain separate simulations for each covariance structure defined by the BY variables. When a BY statement appears, the procedure expects the input DATA= data set to be sorted in the order of the BY variables. If a CONDITION statement is used along with a BY statement, there must be a _TYPE_=’COND’ observation within each BY group. Note that if a BY statement is specified, the number of realizations specified by the NUMREAL= option are produced for each BY group.