Hi, I have two data sets; one is a population and the other a sample of that population. I am trying to plot both on the same trellis display.
# Example data set with two numerical attributes and two categorical pop <- data.frame(var1=rnorm(2000, 2000, 500), var2=rnorm(2000, 2000, 500)) cat<-(runif(2000)<=.5)+0 for(i in 1:length(cat)){ if(cat[i] == 0){ pop[i,"cat1"] = "this" } else{ pop[i,"cat1"] = "that" } } cat<-(runif(2000)<=.5)+0 for(i in 1:length(cat)){ if(cat[i] == 0){ pop[i,"cat2"] = "here" } else{ pop[i,"cat2"] = "there" } } #Extract sample sam <- pop[sample(1:2000,50),] #Combine data sets x <- make.groups(pop, sam) #Create trellis display densityplot(~var1 + var2 | cat1 * cat2, data=x, groups=which, plot.points=FALSE, auto.key=list(columns=2)) This does not produce what I want. I would like four density plots in each panel; var1 and var2 from the sample data as solid lines and var1 and var2 from the population data as dotted lines with matching colours. densityplot(~ var1 + var2 | cat1 * cat2, data=x, groups=which, panel=panel.superpose, panel.groups = function(x, y,...){ panel.densityplot(x, ...) }) ... gives the same result. I've read "The panel function demystified" section of the book many times and still find the panel function mystifying. Could someone please explain how to do this and also how it works. Thankyou ______________________________________________ R-help@r-project.org 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.