1.
Select Help > Sample Data Library and open InjectionMolding.jmp.
2.
Select Analyze > Fit Model.
3.
Click Run.
5.
In the InjectionMolding.jmp sample data table, right-click on the continuous icon next to Hold Time in the Columns panel, and select Nominal.
6.
Select Analyze > Fit Y by X.
7.
Select Shrinkage Residual and click Y, Response.
8.
Select Hold Time and click X, Factor.
9.
Figure 9.6 Residual by Dispersion Effect
In this plot it is easy to see the variance go up as the Hold Time increases. This is done by treating Hold Time as a nominal factor.

Help created on 7/12/2018