see ?factor and ?as.factor. On ordered factors you can technically do a spearman without problem, apart from the fact that a spearman test by definition cannot give exact p-values with ties present.
x <- sample(c("a","b","c","d","e"),100,replace=T) y <- sample(c("a","b","c","d","e"),100,replace=T) x.ordered <- factor(x,levels=c("e","b","a","d","c"),ordered=T) x.ordered y.ordered <- factor(y,levels=c("e","b","a","d","c"),ordered=T) y.ordered cor.test(x.ordered,y.ordered,method="spearman") require(pspearman) spearman.test(x.ordered,y.ordered) R commander has some menu options to deal with factors. R commander also provides a scripting window. Please do your students a favor, and show them how to use those commands. Cheers Joris On Thu, Jun 3, 2010 at 2:25 PM, Iasonas Lamprianou <lampria...@yahoo.com>wrote: > Dear colleagues, > > I teach statistics using SPSS. I want to use R instead. I hit on one > problem and I need some quick advice. When I want to work with ordinal > variables, in SPSS I can compute the median or create a barchart or compute > a spearman correlation with no problems. In R, if I "read" the ordinal > variable as numeric, then I cannot do a barplot because I miss the category > names. If I read the variables as characters, then I cannot run a spearman. > How can I read a variable as numeric, still have the chance to assign value > labels, and be able to get table of frequencies etc? I want to be able to do > all these things in R commander. My students will probable be scared away if > I try anything else other than R commander (just writing commands will not > make them happy). > > I hope I am not asking for too much. Hopefully there is a way > > > > > ______________________________________________ > 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. > -- Joris Meys Statistical Consultant Ghent University Faculty of Bioscience Engineering Department of Applied mathematics, biometrics and process control Coupure Links 653 B-9000 Gent tel : +32 9 264 59 87 joris.m...@ugent.be ------------------------------- Disclaimer : http://helpdesk.ugent.be/e-maildisclaimer.php [[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.