I'm not sure how returning an incorrect result is ever a 'positive' feature but at least the documentation could more clearly warn users that this method behaves differently in these cases -- summary(rock[,1]) vs summary(rock[,1:2]) -- and that the method can and does return incorrect results without any warning messages.
I would encourage anyone teaching introductory R to look at the 'epicalc' package. The re-vamped function 'summ' in that package returns correct results regardless - summ(rock), summ(rock$area). In addition, when you only ask for one column you not only get the correct results, you also get a bonus distribution plot. I'd would like all of our students to use R, but little things like this are huge stumbling blocks for them. -jeanne [[alternative HTML version deleted]] ______________________________________________ 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.