Am 14.09.2007 um 15:54 schrieb Petr PIKAL: >> Petr PIKAL wrote: >>> Hi >>> >>> [EMAIL PROTECTED] napsal dne 14.09.2007 13:50:58: >>> >>> >>>> Birgit Lemcke wrote: >>>> >>>>> Am 14.09.2007 um 12:05 schrieb Peter Dalgaard: >>>>> >>>>> >>>>>> S Ellison wrote: >>>>>> >>>>>>>>>> Peter Dalgaard <[EMAIL PROTECTED]> 14/09/2007 09:26:16 >>>> >>>>>>>>>> >>>>>>>>>> >>> >>> >>> <snip> >>> >>> >>> >>>>>> Yes, but.... >>>>>> >>>>>> I don't think lme() will do better than what you can do by hand: > Get >>>>>> >>> two >>> >>>>>> independent estimates of mu1-mu2 (one estimate from the pairs and > one >>>>>> from the singlets), compute a weighted average using the >>>>>> s.e.'s and > >>>>>> >>> test >>> >>>>>> that against zero (possibly after testing them for equality for > good >>>>>> measure). This is easy if you use a plug-in approach: first >>>>>> assume >>>>>> >>> that >>> >>>>>> the s.e. are known, then plug in their empirical value. The >>>>>> tricky >>>>>> >>> bit >>> >>>>>> is to calculate the DF in the style of Welch's test. >>>>>> >>>>> I apologise but I really can not follow your > explanations. >>>>> I am R and Stastistics Beginner. >>>>> >>>>> What do you mean with mu1-mu2 and what are s.e.´s? >>>>> >>>>> >>>> That was a reply to S. Ellison. If you don't understand it, don't > worry; >>>> you'll probably need to read a book chapter or more about weighted >>>> analyses to get up to speed for that. >>>> >>>> mu1, mu2 : (theoretical) mean for group 1, 2 >>>> s.e.: standard error >>>> >>> >>> But as Birgit actually does not have any paired values, according to > the >>> data she had sent, she can not do paired t.test at all. The only way > is to >>> compare averages from each vector by non paired t.test or to get >>> some > new >>> values for which she have counterparts. >>> >> True, for that particular set of data. I did make that point in my >> first >> reply (tried to, anyways), but I didn't repeat it the second time. >> >> If you look back, you'll see that Birgit was also doing >> >> TTest75<-t.test(Fem75, Mal75, alternative= "two.sided", paired= TRUE) >> >> and presumably there are several similar sets of data. This >> "works" in > the >> sense that it produces a test, but one could get the suspicion >> that it > is only >> using a small subset of available data if the dropout rate is > approaching that >> of Fem66/Mal66. Hence the discussion of the general case. > > I see, sorry I did not noticed before. But everything depends on which > hypotheses she wants to test. She told us about 334 different plant
348 > species (male and female) and if she wants to test if male and > female is > different yes > she does not have many other options. > > Petr > >> >>> Regards >>> Petr >>> >>> >>> >>> >>>>> Once again thank you for your help. >>>>> >>>>> Birgit >>>>> >>>>> >>>>> >>>>> >>>>> >>>>>> -- 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 >>>>>> >>>>>> >>>>>> >>>>> Birgit Lemcke >>>>> Institut für Systematische Botanik >>>>> Zollikerstrasse 107 >>>>> CH-8008 Zürich >>>>> Switzerland >>>>> Ph: +41 (0)44 634 8351 >>>>> [EMAIL PROTECTED] >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> >>>> -- >>>> 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. >>>> >>> >>> ______________________________________________ >>> 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. >>> >> >> >> -- >> 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. > > ______________________________________________ > 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. Birgit Lemcke Institut für Systematische Botanik Zollikerstrasse 107 CH-8008 Zürich Switzerland Ph: +41 (0)44 634 8351 [EMAIL PROTECTED] [[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.
