Thank you Joris, I'll have a look into the commands you sent me. They look convincing. I hope my students will also see them in a positive way (although I can force them to pretend that they have a positive attitude)!
Dr. Iasonas Lamprianou Assistant Professor (Educational Research and Evaluation) Department of Education Sciences European University-Cyprus P.O. Box 22006 1516 Nicosia Cyprus Tel.: +357-22-713178 Fax: +357-22-590539 Honorary Research Fellow Department of Education The University of Manchester Oxford Road, Manchester M13 9PL, UK Tel. 0044 161 275 3485 iasonas.lampria...@manchester.ac.uk --- On Thu, 3/6/10, Joris Meys <jorism...@gmail.com> wrote: From: Joris Meys <jorism...@gmail.com> Subject: Re: [R] ordinal variables To: "Iasonas Lamprianou" <lampria...@yahoo.com> Cc: r-help@r-project.org Date: Thursday, 3 June, 2010, 14:35 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.