Hello David, I wanted to thank you for pointing to this code for performing posthoc friedman test. I just used this example to create a function to perform this test (and also added some illustrative flexible plots to the mix), here: http://www.r-statistics.com/2010/02/post-hoc-analysis-for-friedmans-test-r-code/
Best, Tal ----------------Contact Details:------------------------------------------------------- Contact me: tal.gal...@gmail.com | 972-52-7275845 Read me: www.talgalili.com (Hebrew) | www.biostatistics.co.il (Hebrew) | www.r-statistics.com (English) ---------------------------------------------------------------------------------------------- On Mon, Sep 21, 2009 at 3:35 AM, David Winsemius <dwinsem...@comcast.net>wrote: > > On Sep 20, 2009, at 9:05 PM, j...@terraspark.com wrote: > > Hi there all, >> >> This is my first post to the list and I'll first say a few things: >> - R is great! >> - The archives of this list have helped me solve all of my >> problems/questions so far >> - I only know enough statistics "to be dangerous" >> >> I'm looking for a way to do post-hoc tests for the Friedman test. I have a >> dataset from a within-subjects design with 5 conditions where some of the >> dependent variables are ordinal, resulting from (summed) likert-scaled >> questionnaire data. >> >> From what I've read, I could use a wilcox.test on pairs of conditions and >> adjust the p level, but is there something in R that does a better >> job/automates this. >> >> I've seen references to the npmc package but that doesn't seem to do what >> I'm looking for, because it only accepts a data frame with two columns - >> i.e. there's no way to specify grouping/subject identifiers. >> >> Thanks, >> > > There is a worked example in the coin package for using a permutation test > to examine differences after a Friedman test. The authors, Hothorn , Hornik > , van de Wiel, and Zeileis, call this method the > Wilcoxon-Nemenyi-McDonald-Thompson test and cite: Hollander & Wolfe (1999), > page 295 > > > http://finzi.psych.upenn.edu/R/library/coin/html/SymmetryTests.html > > -- > David Winsemius, MD > Heritage Laboratories > West Hartford, CT > > ______________________________________________ > 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. > [[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.
