[R] Overdispersion in the lmer models
dwinsemius at comcast.net
Mon Oct 13 21:30:50 CEST 2008
I shouldn't have sent my unhelpful reply to the entire list, since it
is now glaringly obvious that I did not carefully read your original
question. You are outside my experience, since I have not used lme4,
but I wonder if questions about over-dispersion shouldn't be handled
by examining grouped residuals? According to the documentation, "mer"
models have a resid method, although the help page it links to appears
to be "under construction".
On Oct 13, 2008, at 4:46 AM, Fucikova, Eva wrote:
> Dear David,
> Thank you for such a fast answer. Unortunatelly, your suggestion does
> not work for lmer for some reason. I can probably try to run the model
> without random effect to find out the overdispersion in the glm.
> Anyway, thank you very much.
> Yours sincerely,
> -----Original Message-----
> From: David Winsemius [mailto:dwinsemius at comcast.net]
> Sent: maandag 13 oktober 2008 3:42
> To: Fucikova, Eva
> Cc: r-help at r-project.org
> Subject: Re: [R] Overdispersion in the lmer models
> Have you considered using glm() with family = "quasipoisson" or
> = quasibinomial ? I know from experience that the quasipoisson choice
> reports an index of dispersion.
> David Winsemius
> On Oct 12, 2008, at 4:55 AM, Fucikova, Eva wrote:
>> Dear All,
>> I am working with linear mixed-effects models using the lme4 package
>> in R. I created a model using the lmer function including some main
>> effects, a three-way interaction and a random effect.
>> Because I work with a binomial and poisson distribution, I want to
>> know whether there is overdispersion in my data or not. Does anybody
>> know how I can retrieve this information from R?
>> Thank you in advance,
>> Eva Fucikova
>> [[alternative HTML version deleted]]
>> R-help at r-project.org mailing list
>> PLEASE do read the posting guide
>> and provide commented, minimal, self-contained, reproducible code.
More information about the R-help