Standard least squares fits mixture models using the parameterization suggested in Scheffé (1958). The parameters for this model cannot easily be used to judge the effects of the mixture components. The Cox Mixture model is a reparameterized and constrained version of the Scheffé model. Using its parameter estimates, you can derive factor effects and the response surface shape relative to a reference point in the design space. See Cornell (1990) for a complete discussion.
1.
Select Help > Sample Data Library and open Five Factor Mixture.jmp.
2.
Select Analyze > Fit Model.
3.
Select Y1 and click Y.
4.
Select X1 through X5.
5.
Select Macros > Mixture Response Surface.
6.
Click Run.
Figure 2.39 Cox Reference Mixture Window
9.
Figure 2.40 Cox Mixtures

Help created on 10/11/2018