I am doing a RSM (CCD) design to optimize my works based on the two response variables (Y1 and Y2).The Y1 is linear and the Y2 is quadratic. In this case, how do I optimize my works?
I am confused, because I have conducted the experiments at corner points, axial points and center points. When I try to optimize them by using RSM (CCD) the Y1 is not fit to the model due to the lack of fit is significant, Prob>F is lower than 0.05 (it should be linear as when conducting linear regression the R-square is higher and the lack of fit is insignificant) however the Y2 is fit well to the model that developed in RSM due to high R-square and the lack of fit is insignificant (Prob>F is higher 0.05).