Dear Pieter, I suppose that you have attached your data.frame and then messed up the Distance variable. Therefore do not use attach(your.data.frame) but use the data = your.data.frame argument in your models.
If that does not solve the problem, then send us a reproducible example of your problem (= models + dummy data). HTH, 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 Pieter Deleu Verzonden: maandag 14 december 2009 16:20 Aan: r-h...@stat.math.ethz.ch Onderwerp: [R] Bug in lnme package? Hi! Something funny happens to me in lnme. I don't know if it's a bug or not. Here's a short sketch of the problem (you could skip the introduction and just go to the models): I'm counting the number of spider webs ( = response variable) along two rivers, with a two-level treatment: free-flowing and dammed. There are three field sites (random factor) along each river, and measurements are done six times (= random factor for repeated measurements). Webs are counted on four different distances along the river (fixed effect), with six plots at each distance. My model looks like this: * Model<-lme(Webslog1~Treatment*Distance,random=~Week|Uniquesite/Uniqueplo t,method="REML") * I want to leave out the interaction between Treatment and Distance, so that would go like this: * >ModelNoInteraction<-lme(Webslog1~Treatment+Distance,random=~Week|Unique >site/Uniqueplot,method="REML") * However, then i get the error message:* "Error in model.frame.default(formula = ~Week + Webslog1 + Treatment + : invalid type (list) for variable 'Distance' "* I first thought that it is for some reason just not allowed to leave out the interaction. But when i try to run the first model again, i get the same error message! Therefore i thought the thing could be a bug. The whole thing looks like this: *> Model<-lme(Webslog1~Treatment*Distance,random=~Week|Uniquesite/Uniqueplo t,method="REML") > ModelNoInteraction<-lme(Webslog1~Treatment+Distance,random=~Week|Uniques ite/Uniqueplot,method="REML") Error in model.frame.default(formula = ~Week + Webslog1 + Treatment + : invalid type (list) for variable 'Distance3' > Model<-lme(Webslog1~Treatment*Distance,random=~Week|Uniquesite/Uniqueplo t,method="REML") Error in model.frame.default(formula = ~Week + Webslog1 + Treatment + : invalid type (list) for variable 'Distance3'* *>* Someone any idea? Bug or just my poor R skills? Thanks for having a look at this! Pieter [[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. 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.