Reconsider the wave soldering experiment in Problem 12.16. Suppose that it was necessary to fit a complete quadratic model in the controllable variables, all main effects of the noise variables, and all controllable variable–noise variable interactions. What design would you recommend?.

Problem 12.16

Rework Problem 12.15 using the I-criterion to construct the design. Compare this design to the D-optimal design in Problem 12.15. Which design would you prefer?

Problem 12.15

Suppose that there are four controllable variables and two noise variables. It is necessary to fit a complete quadratic model in the controllable variables, the main effects of the noise variables, and the two-factor interactions between all controllable and noise factors. Set up a combined array design for this by modifying a central composite design.