[R] Mixed effects model with binomial errors - problem

Ben Bolker bolker at ufl.edu
Wed Sep 10 15:55:26 CEST 2008


RFTW <l.temarvelde <at> nioo.knaw.nl> writes:


> Our question is if the proportion of visits to the experimental tree, in
> relation to the total number of visits to both trees differs between
> treatments.
> 
> We have made treatment and individual into a factor
> All individuals were subjected to a maximum of 4  treatments, so
> 'individual' is a random factor
> 
> We came up with this model:
> model1<-lmer(cbind(ExpTree,Total visits-ExpTree)~ Treat +(1|Ind),method="ML"
> , family=binomial, data=r))

  why not leave out method="ML" and see what happens?
  for the current iteration of lmer, REML is not a possibility
in any case.  The default "Laplace" method should work OK.

   I'd be slightly worried about your variable name with a space
in it (`Total visits`) -- are you sure that is working as expected?

  For further questions along these lines I would suggest
e-mailing r-sig-mixed-models at lists.r-project.org instead ...

  Ben Bolker



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