1. Post on R-sig-mixed-models instead. Much more expertise and relevance there.
2. I would forget about mixed effects and treat the locations as fixed. With only 5, you don't have enough information to estimate the variance component with any precision anyway. 3. Feel free to ignore (2) and defer to the experts at (1). Cheers, Bert On Tue, Sep 25, 2012 at 8:52 AM, Christof Kluß <ckl...@email.uni-kiel.de> wrote: > Hi, > > I want to fit nonlinear dose-response curves, as "fun(X,a,b,c)", for > each of our 5 trail locations. Our data basis is something like > > location plot year dose response > > For each location there are 4 plots as repetitions (over 3 years). So > the interactions "location*year" and "location*plot" should be random > effects. > > There are some examples in "Mixed-Effects Models in S and S-PLUS" > (Pinheiro and Bates), but I do not see how they can help me for my > model. Of course I can start with something like > > mod <- nlme(response ~ fun(dose,a,b,c) > , fixed = list(a ~ 1, b ~ 1, c ~ 1) > , random = list(a ~ 1, b ~ 1, c ~ 1) > , groups = ~location > , data=dat > , start= ... ) > > But that is not what I want. How do you describe that you want one fit > for each of the five locations and that "location*year" and > "location*plot" or something similar are random effects? > > Do you have some other examples that fit better to this problem setting? > I welcome any tips. > > thx > Christof > > ______________________________________________ > 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. -- Bert Gunter Genentech Nonclinical Biostatistics Internal Contact Info: Phone: 467-7374 Website: http://pharmadevelopment.roche.com/index/pdb/pdb-functional-groups/pdb-biostatistics/pdb-ncb-home.htm ______________________________________________ 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.
