The Kruskal-Wallis test is a special case of the proportional odds ordinal logistic model. You can get any contrast you want by testing regression coefficients. In a couple of weeks the rms package's contrast function will allow for individual confidence intervals of effects that together have a 0.05 type I error, by using the multcomp package (called automatically from contrast.rms). Frank
Iasonas Lamprianou wrote > > Thank you for the result, I will have a look at the link. > > > Dr. Iasonas Lamprianou > Department of Social and Political Sciences > University of Cyprus > > >>________________________________ >> From: Tal Galili <tal.galili@> >>To: Iasonas Lamprianou <lamprianou@> >>Cc: "r-help@" <r-help@> >>Sent: Thursday, 12 January 2012, 10:48 >>Subject: Re: [R] kruskal wallis post hoc? >> >> >>Hi Iasonas , >>This is a stat question and not an R question. >>But the general answer is that it could happen :) >> >> >>The R question would have been if their is a Tukey HSD for kruskel.test, the answer is yes: >>http://stats.stackexchange.com/questions/17342/is-there-a-nonparametric-equivalent-of-tukey-hsd >> >>But if you didn't get any significant result from the pairwise comparison, I would say that the post hoc correction wouldn't help you (it could be that the reason for this significance is based on some weird contrast...) >> >> >>Best, >>Tal >> >> >> >> >> >> >> >> >>----------------Contact Details:------------------------------------------------------- >>Contact me: Tal.Galili@ | 972-52-7275845 >>Read me: www.talgalili.com (Hebrew) | www.biostatistics.co.il (Hebrew) | www.r-statistics.com (English) >>---------------------------------------------------------------------------------------------- >> >> >> >> >> >>On Thu, Jan 12, 2012 at 8:35 AM, Iasonas Lamprianou <lamprianou@> wrote: >> >>Dear all, >>> >>>I run a kruskal wallis test and found significant results. Then, I conducted all pairwise comparisons and found no significant results. Could anyone please give me a hint as to why this happens or redirect me towards a specific web page where I can find more info? (I used alpha=5% and made no bonferroni or other correction for the pairwise comparisons) >>>Thank you >>> >>> >>>Dr. Iasonas Lamprianou >>>Department of Social and Political Sciences >>>University of Cyprus >>> [[alternative HTML version deleted]] >>> >>> >>>______________________________________________ >>>R-help@ 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@ 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. > ----- Frank Harrell Department of Biostatistics, Vanderbilt University -- View this message in context: http://r.789695.n4.nabble.com/kruskal-wallis-post-hoc-tp4288008p4288894.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ 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.
