As an example, we will show how to do this when there are three variables: "Y" (target variable), "X" (explanatory variable), and "group."
Select "Fit Model" from the menu, select "Y" as the response variable, "X" and "Group" from the "Column Selection List," and select "Full Factorial Design" from the "Macro" button (X, Group, and X*Group will be specified).
Look at the statistics for the interaction term (X* group) in the Effect Tests section of the report to determine whether they are significant. If they are significant, you can conclude that the slopes are different.
This type of analysis is called analysis of covariance (ANCOVA), and an example analysis can be found in the JMP manual, "Finding Regression Models."
FAQ # 2092
