Falco tinnunculus <kestrel78 <at> gmail.com> writes: > How do I run interaction between to categoric variables in lme()? > > I tried this: > > > lmefit1<- lme(Handling ~Mass+factor(Prey)+factor (Decap)+ > factor(Prey)*factor(Decap), random = ~ 1 |Place, data=nestling1) > > Error in MEEM(object, conLin, control$niterEM) : > Singularity in backsolve at level 0, block 1
First, I would suggest that you make Prey, Decap factors in your data frame. Makes for a much easier reading, and fewer errors if you test nestling1$Prey = as.factor(nestling1$Prey) nestling1$Decap = as.factor(nestling1$Decap) lmefit1<- lme(Handling ~Mass+Decap*Prey, random = ~ 1 |Place, data=nestling1) You should not write Prey+Decap+Prey*Decap. I you want to do it explicitly, used the colon instead Prey+Decap+Prey:Decap or, let lme do the dirty (i.e. in most cases correct) work: Prey*Decap which will expand to what you need. If you still get the error message, it's your data: you want to much from them. Check if you have enough degrees of freedom left, or if the data set is degenerate by not including a sufficient number of pairing. Dieter ______________________________________________ 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.
