BY variables are optional (in most reports) variable specifications whose values define groups of observations, such as hour, month, or year. BY variables can enable analyses to be performed separately on different groups as defined by that variable. Choosing a BY variable such as gender (ADSL variable = SEX), for example, groups the subjects by gender and conducts two separate analyses: one for males and one for females.
Click to open an Add window (shown below) listing all of the variables in FI and any specified supplemental data set.