Hello: That's because the required input should be a symmetric matrix with all the comparisons, e.g., it should have the self-comparisons diagonal. In an hypotetical case with two treatments, the pairwise-comparison test output is something like that:
A B B 0.80 - but multcompView requires an input like that one: A B A 1 - B 0.80 1 That means you should add a new row and column for your missing treatments and, then, a diagonal of "1"s meaning that each treatment compared with itself will result in a p-value of 1 (maximal identity). Then, the new matrix could be piped succesfully. Regards, Retama goz wrote: > > hello, > > i try to use the multcomp letters, but i have problems with my results : > > here is my pvalue matrix (from a pairwise.t.test) : > > pair=pairwise.t.test(...) > pair$p.value > > 0 B BxS > B 0.01727 - - > BxS 0.00013 0.00226 - > S 0.87555 0.02610 0.00027 > > > i was thiking to have something like that : > 0 B S BxS > a b a c > > but function return : > >> multcompLetters(pair$p.value) > B BxS S > "a" "b" "a" > > > first question : why the 0 traitement doesn't appears in result ? > second : why the results differs than what i expected ? > > many thanks. > > -- View this message in context: http://www.nabble.com/Letter-based-representation-of-pairwise-comparisons-tp21350364p25769894.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.