What is the correct way to specify a DOE factor that is a discrete numerical variable?
I was trying to duplicate an analysis in a paper by Christopher Nachtsheim and @bradleyjones called Split-Plot Designs: What, Why, and How, Journal of Quality Technology, Vol. 41, No. 4, October 2009. They use the Box et al data for studying the corrosion resistance of steel bars (attached image). In a split-plot design, Temp is treated as a hard-to-change (whole plot) factor with three levels: 36...
jay_holavarri