Am 14.09.2007 um 14:27 schrieb Peter Dalgaard: > 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.
In my case the other vectors contain about 10 or 15 missing values. So as I understand this will only a little reduce the accuracy of my tests. But for the future and for people like me that are not yet so familiar with R, it would be fine to have a function for example for a T-Test, that is able to use all the data inspite of missing values in pairs. If there is already a function that is doing that, I apologise, but I haven´t found one. But now as we would say in Germany: I will be quiet when adults are talking. Kind regards Birgit > >> 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. 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.
