Stat > DOE > Mixture > Factorial Plots > check Interaction > Setup
Allows you to select the process variables to include in the interaction plot.
Responses: Select the column(s) containing the response data. When you enter more than one response variable, Minitab displays a separate plot for each response.
Process Variables to Include in Plots Use the arrow buttons to move terms from one list to the other. Select a term in one of the lists, then click an arrow button. The double arrows move all the terms in one list to the other. You can also move a term by double-clicking it.
Available: Lists all process variables in your model.
Selected: Lists all process variables that will be included in the interactions plot(s). You can have up to 7 process variables in the Selected list. Minitab draws all two-way interactions of the selected process variables.