Dear Thomas, I have been running simulations in order me to understand this problem! I have found something online where the absolute median difference is computed and permutations are ran to compute a p-value. Is such a test (if I can call it a test) tests the null hypothesis that median group 1 = median group 2?

Thank you in advance for your help. Regards, Cheba 2010/4/6 Thomas Lumley <tlum...@u.washington.edu> > > > None of them. > > - mood.test() looks promising until you read the help page and see that it > does not do Mood's test for equality of quantiles, it does Mood's test for > equality of scale parameters. > - wilcox.test() is not a test for equal medians > - ks.test() is not a test for equal medians. > > > Mood's test for the median involves dichotomizing the data at the pooled > median and then doing Fisher's exact test to see if the binary variable has > the same mean in the two samples. > > median.test<-function(x,y){ > z<-c(x,y) > g <- rep(1:2, c(length(x),length(y))) > m<-median(z) > fisher.test(z<m,g)$p.value > } > > Like most exact tests, it is quite conservative at small sample sizes. > > -thomas > > > On Tue, 6 Apr 2010, cheba meier wrote: > > Dear all, >> >> What is the right test to test whether the median of two groups are >> statistically significant? Is it the wilcox.test, mood.test or the >> ks.test? >> In the text book I have got there is explanation for the Wilcoxon (Mann >> Whitney) test which tests ob the two variable are from the same population >> and also ks.test! >> >> Regards, >> Cheba >> >> [[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. >> >> > Thomas Lumley Assoc. Professor, Biostatistics > tlum...@u.washington.edu University of Washington, Seattle > > [[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.