Thanks for the hint. I found out how to specify contrasts in multcomp using function contrMat: https://stats.stackexchange.com/questions/104028/r-multcomp-contrasts-for-tukey This is about Tukey's test, but the principle is the same for all tests
However, it seems that repeated t-tests with pooled variance are not supported in multcomp: http://www.inside-r.org/packages/cran/multcomp/docs/contrMat Am I wrong? If not, how could I do repeated t-tests for specific contrasts? Thank you Andreas On Wed, Jun 11, 2014 at 10:28 AM, ONKELINX, Thierry < thierry.onkel...@inbo.be> wrote: > Have a look at the multcomp package. The examples in glht() demonstrate > how to specify the required contrasts. > > Best regards, > > ir. Thierry Onkelinx > Instituut voor natuur- en bosonderzoek / Research Institute for Nature and > Forest > team Biometrie & Kwaliteitszorg / team Biometrics & Quality Assurance > Kliniekstraat 25 > 1070 Anderlecht > Belgium > + 32 2 525 02 51 > + 32 54 43 61 85 > thierry.onkel...@inbo.be > www.inbo.be > > To call in the statistician after the experiment is done may be no more > than asking him to perform a post-mortem examination: he may be able to say > what the experiment died of. > ~ Sir Ronald Aylmer Fisher > > The plural of anecdote is not data. > ~ Roger Brinner > > The combination of some data and an aching desire for an answer does not > ensure that a reasonable answer can be extracted from a given body of data. > ~ John Tukey > > > -----Oorspronkelijk bericht----- > Van: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] > Namens Andreas Maunz > Verzonden: woensdag 11 juni 2014 10:02 > Aan: r-help@r-project.org > Onderwerp: [R] aov + pairwise.t.test: only selected pairs > > Hi, > > I have a 1-way anova result and want to do a post test. > > I want to do pairwise t-tests where the global variance is taken into > account (i.e. a real post test on the anova result, not multiple simple t > tests on the samples). > > I understand I should use pairwise.t.test() for that. However, it does not > allow me to select specific pairs, it always analyzes all pairs. How can I > analyze specific pairs only? > > Thanks > Andreas > > [[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. > * * * * * * * * * * * * * D I S C L A I M E R * * * * * * * * * * * * * > Dit bericht en eventuele bijlagen geven enkel de visie van de schrijver > weer en binden het INBO onder geen enkel beding, zolang dit bericht niet > bevestigd is door een geldig ondertekend document. > The views expressed in this message and any annex are purely those of the > writer and may not be regarded as stating an official position of INBO, as > long as the message is not confirmed by a duly signed document. > > [[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.
