Hello Hugo, Thank you for your reply. This is a snap shot of what my data looks like:
Presencebsence Habitatype Substratetype Width Banktype BankIncline Bankheight Waterdepth 0 Lake Rocksgravel 600 Earth 0.45 less1 greater2 0 Lake Rocksgravel 600 Earth 0.45 less1 greater2 1 Lake Rocksgravel 600 Earth 0.45 less1 greater2 0 Lake Rocksgravel 600 Earth 0.45 less1 greater2 0 Lake Rocksgravel 600 Earth 0.45 less1 greater2 0 Stream Rocksgravel 1 Rocks 0.45 less1 025to05 0 Stream Rocksgravel 1 Rocks 0.45 less1 025to05 0 Stream Rocksgravel 1 Rocks 0.45 less1 025to05 0 Stream Rocksgravel 1 Rocks 0.45 less1 025to05 I am trying to find out if any off the above factors so substrate type, width, bank type etc have an effect on the presence/absence of the species in question. But as stated below I keep getting an error message up and I have no idea how to fix it in order for me to fun the lmer. Sophie > From: hugo.mildenber...@web.de > To: r-help@r-project.org > CC: england...@hotmail.com > Subject: Re: [R] Help with lmer > Date: Fri, 24 Jun 2011 17:19:00 +0200 > > Sophie, > > I'm myself quite new to linear mixed effect models, but "PresenceAbsence" > sounds like > a binary response variable. So wouldn't be > > m1<-lmer(Presencebsence~Habitatype*Width+(1|Sitename),familiy=binomial) > > the first thing to try? There is also a special mailing list for linear - > mixed -effect > models: > > r-sig-mixed-mod...@r-project.org > > But with numeric problems like this one you really should provide a self > contained > example (i.e. with data), at least the output of str(yourdata), if ever > possible. > > Kind regards > > Hugo > > On Friday 24 June 2011 13:11:23 Sophie Higgins wrote: > > > > Hey, > > I am having trouble with lmer. I am looking at the presence/absence of > > water shrews against habitat and other factors e.g > > so I used this: > > m1<-lmer(Presencebsence~Habitatype*Width+(1|Sitename))summary(m1) > > But i keep getting this error up > > Error in mer_finalize(ans) : Downdated X'X is not positive definite, 16.> > > summary(m1)Error in asMethod(object) : matrix is not symmetric [1,2] > > What does this mean and now can I fix it? > > Sophie > > [[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. [[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.
