This is a brief explanation on the menu for analysis of designs for quantitative factors.
The menu item Response surface model ... creates a response surface
analysis with first order (FO) terms, and potentially also two-factor interactions
(TWI) and/or pure quadratic (PQ) terms. The resulting object has class rsm
and can be postprocessed with the subsequent menu items.
The menu item Steepest slope ... supports moving the experimental range towards a more promising area, based on a first order model or on a second order model with a saddle point.
The menu item Plot response surface ... supports creation of contour, perspective or image plots of a response surface model, and can also be used for linear models with quantitative variables.
It is of course also possible to use other analysis facilities within the R-commander,
or to use the command-line facilities offered in package rsm
and elsewhere.
Ulrike Groemping
Box G. E. P, Hunter, W. C. and Hunter, J. S. (2005) Statistics for Experimenters, 2nd edition. New York: Wiley.