Fitting a model for a two-factor experimental design
I'm trying to fit a model for a two-factor experimental design (2 factors). This is Problem 5.4 in D.C Montgomery book (Design and analysis of experiments 8th ed. Chap 5.The yield of a chemical process is being studied. The two most important variables are thought to be the pressure and the temperature. Three levels of each factor are selected, and a factorial experiment with two replicates is per...