[R-sig-ME] Beta-binomial distributions with lmer?

Christine Griffiths Christine.Griffiths at bristol.ac.uk
Wed Jun 10 15:34:53 CEST 2009

Thanks. I was hoping for a miracle that this had been developed within the 
last couple of months.

I am on the stats learning curve and am not quite sure how flexible to be 
with regards to distributions.  Is quasibinomial acceptable, despite having 
data with a lot of 0s and a lot of 100s?

Many thanks in advance,

--On 10 June 2009 09:18 -0400 Ben Bolker <bolker at ufl.edu> wrote:

>   No.  You can use a quasi-binomial model, although
> the support is a little bit spotty (and beware that
> quasi- models may falsely report inflation of the
> random effects).
>   Ben Bolker
> Christine Griffiths wrote:
>> Hi R users,
>> Just a query as to whether lme4 can handle beta-binomial distributions
>> as I  read that this was not available.
>> If not, any suggestions on how to handle such a distribution to plot the
>> following model:
>> y<-cbind(Biotic,Abiotic)
>> m1<-lmer(y~Treatment+Month.rain+(1|Month)+(1|Block/EnclosureID/Quadrat))
>> y referring to percentage cover of biotic matter.
>> Cheers,
>> Christine
>> _______________________________________________
>> R-sig-mixed-models at r-project.org mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-sig-mixed-models
> --
> Ben Bolker
> Associate professor, Biology Dep't, Univ. of Florida
> bolker at ufl.edu / www.zoology.ufl.edu/bolker
> GPG key: www.zoology.ufl.edu/bolker/benbolker-publickey.asc

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