Graph > Dotplot > choose One Y - Stack Groups > OK
Use to display a dotplot with overlayed groups.
Graph variables: Enter one or more columns of data. Minitab displays a separate graph for each column. (To panel all graphs on the same page, use Multiple Variables.)
Categorical variables for grouping (1-4, outermost first): Enter one to four columns of grouping (categorical) variables. Minitab displays all groups on the same graph. (To panel by one or more variables, use By Variables.) The first variable will be the outermost on the scale and the last will be the innermost.
Stack dots of last categorical variable: Check to display the groups for the last categorical variable on the same dotplot. Each group has a different symbol.