Example of Effect Heredity
Use the Fit Two Level Screening platform to build a model that does not follow effect heredity.
1. Select Help > Sample Data Folder and open Design Experiment/Plackett-Burman.jmp.
2. Select DOE > Classical > Factor Screening> Fit Two Level Screening.
3. Select Percent Reacted and click Y.
4. Select Feed Rate through Concentration and click X.
5. Click OK.
Figure 11.7 Model Contrasts
Note: Since the p-values are obtained using a simulation-based technique, your p-values might not precisely match those shown here.
TheCatalyst*Stir Rate interaction is highlighted, but the Stir Rate main effect is not. In accordance with the principle of Effect Heredity, you should add the Stir Rate main effect to the model. See “Effect Heredity”.
6. Click Make Model.
7. Select Stir Rate and click Add in the Construct Model Effects section.
8. Click Run.
Figure 11.8 Partial Fit Model Report
The ^ symbol to the right of the PValue for Stir Rate and Temperature show that while not significant, these effects are contained in significant higher-order effect.