Graph > Probability Plot > choose Multiple > OK
Use to display overlaid probability plots of multiple variables and/or multiple groups on the same graph.
Graph variables: Enter one or more columns of data.
Categorical variables for grouping (0-3): If graph variable columns contain multiple groups, enter up to three columns of categorical grouping variables. (To panel by one or more variables, use By Variables.)
Graph variables form groups: Check to overlay probability plots for all graph variables on the same graph. (To panel multiple graphs on the same page, use Multiple Variables.)