dye <- read.csv("http://www.stat.ufl.edu/~winner/sta4210/mydata/dye_cotton_rsm.csv", header=TRUE) attach(dye) names(dye) install.packages("rsm") library(rsm) dye.rsm1 <- rsm(KS ~ SO(Temp,Time,Cation)) summary(dye.rsm1) drop1(dye.rsm1) contour(dye.rsm1, ~ Temp + Time, image=TRUE) contour(dye.rsm1, ~ Temp + Cation, image=TRUE) contour(dye.rsm1, ~ Time + Cation, image=TRUE)