Hi, I am trying to plot an interaction.plot with different color for each level of a factor. It has an erratic behavior.
For example, it works for the first interaction.plot below, with the example from the ALDA book, but not with the other plots, from the NPK dataset: # from http://www.ats.ucla.edu/stat/r/examples/alda/ch2.htm tolerance <- read.csv("http://www.ats.ucla.edu/stat/r/examples/alda/data/tolerance1.txt";) tolerance.pp <- read.csv("http://www.ats.ucla.edu/stat/r/examples/alda/data/tolerance1_pp.txt";) attach(tolerance.pp) # fitting the linear model by id fit <- by(tolerance.pp, id, function(bydata) fitted.values(lm(tolerance ~ time, data=bydata))) fit <- unlist(fit) # plotting the linear fit by id interaction.plot(age, id, fit, xlab="age", ylab="tolerance") # plots red for female and green for male interaction.plot(age, id, fit, xlab="age", ylab="tolerance", col=male+2) print(tolerance.pp[id==978|id==514|id==9|id==1105|id==1653,c("id","male")]) data(npk, package="MASS") fit <- by(npk, npk$block, function(bydata) fitted.values(lm(yield ~ N, data=bydata))) fit <- unlist(fit) interaction.plot(npk$N, npk$block, fit, xlab="N", ylab="yield") # fake factor, numeric fac <- c(rep(1,12),rep(2,12)) # plots everything in black interaction.plot(npk$N, npk$block, fit, xlab="N", ylab="yield",col=fac) cbind(npk$block,fac) # plots everything transparent fac <- as.factor(fac) interaction.plot(npk$N, npk$block, fit, xlab="N", ylab="yield",col=as.numeric(npk$fac)) ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
