Birgit Lemcke wrote: > Thanks for your answer. > > First I will show you both vectors: > [...] > > I tried this (complete.cases(Fem66, Mal66)) and you are right, it > gives me back: > > (complete.cases(Fem66, Mal66)) > [1] FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE > FALSE FALSE FALSE [....] > I thought the t.test is a comparison of means and why can I not use it > if I have a lot of missing values. Is the reason that I use the paired > option? > What is different in the calculation using paired? > > Ah ja this seems to be the case: > > T66<-t.test(Mal66, Fem66, alternative= "two.sided") > > T66 > > > Welch Two Sample t-test > > data: Mal66 and Fem66 > t = -0.4881, df = 49.229, p-value = 0.6277 > alternative hypothesis: true difference in means is not equal to 0 > 95 percent confidence interval: > -1.4637045 0.8915906 > sample estimates: > mean of x mean of y > 5.096552 5.382609 > > I use the paired option because may plants (male and female) belong to > the same species (and because may boss said that I have to use paired > in this case) Don't do what your boss says, do what is right! (It might of course be the same thing). So pair #1 is one species, pair #2 another species, up to 331 different species?
> So what can I do now to solve my problem? > > Do you think I should not use paired=TRUE? You *can* only use it when you have pairs, and you must do it then, to correct for intra-pair correlation. The drawback is that it looks only at complete pairs, throwing away all the singlets. It is possible to recover the information from the singlets , basically by combining a paired test for the pairs and an unpaired one for the singlets. (Someone must have written this down, but I'm afraid I don't have a nice reference). -- O__ ---- Peter Dalgaard Øster Farimagsgade 5, Entr.B c/ /'_ --- Dept. of Biostatistics PO Box 2099, 1014 Cph. K (*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918 ~~~~~~~~~~ - ([EMAIL PROTECTED]) FAX: (+45) 35327907 ______________________________________________ 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.
