Have a look at ?varClasses. You could you something like varIdent(form = ~ 1|areatrai) or varExp(form = ~areatrai)
R-sig-mixed-models is a better list for this kind of questions. Thierry ------------------------------------------------------------------------ ---- ir. Thierry Onkelinx Instituut voor natuur- en bosonderzoek team Biometrie & Kwaliteitszorg Gaverstraat 4 9500 Geraardsbergen Belgium Research Institute for Nature and Forest team Biometrics & Quality Assurance Gaverstraat 4 9500 Geraardsbergen Belgium tel. + 32 54/436 185 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 Tursiops > Verzonden: vrijdag 21 mei 2010 16:14 > Aan: r-help@r-project.org > Onderwerp: [R] lme: model variance and error by group > > > Hello > I am trying to reproduce a mixed regression model published > in (J Evol Biol 12:94-102) with PASW 17.03. The authors used > SAS to fit the model using the following syntaxis: > > proc mixed nobound; > class area individ trait; > model a = side trait area side*trait side*area > trait*area/ddfm = satterthwaite solution; random intercept > side/subject = individ group = areatrai; repeated/local = > quad(areatrai) subject = individ; run; > > The model specifies separate variance components and error > variances for the grouping "areatrai" variable. This is > indicated by "group= areatrai" > and "local = > quad (areatrai)", respectively. > > Since I currently have no access to SAS and this part of the > analysis is absolutely central to my research, I would be > very grateful if someone can tell whether it is possible to > model the variance and error by group using lme or any other > R package for linear mixed models. > > Any help will be much appreciated. > > Thanks > > > > -- > View this message in context: > http://r.789695.n4.nabble.com/lme-model-variance-and-error-by- > group-tp2226207p2226207.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. > Druk dit bericht a.u.b. niet onnodig af. Please do not print this message unnecessarily. 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. ______________________________________________ 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.
