Guys;

Really thanks for your help!!! Always with lots of solutions!

Thanks

On 20 December 2011 15:59, mikhail matz <matz@mail.utexas.edu> wrote:

> Hey Ricardo -
>
> I faced this problem myself very recently, and there is a recent exchange
> on the subject which seems to be an easy solution. Look up
> R-sig-mixed-models Digest, Vol 47, Issue 53; thread by David Stainbrook.
> Briefly, you can effect modeling with negative binomial distribution (which
> takes care of the overdispersion) on counts data by using lognormal poisson
> distribution. You just have to include a random effect corresponding to
> every observation in your data (that is, add something like (1|index) to
> the formula) and specify poisson family (which will by default imply
> log-link).  You will get a warning ("Number of levels of a grouping factor
> for the random effects is *equal* to n, the number of observations." ) but
> this does not seem to matter. There is even a reference to a paper laying
> down the theory: Elston et al, Parasitology (2001), 122, 563-569.
>
> cheers
>
> Misha Matz




-- 
==========================================
Ricardo Ribeiro de Castro Solar (Curriculo
Lattes<http://lattes.cnpq.br/9924177207371692>
)
MSc. em Entomologia - Doutorando - PPG Entomologia
Laboratório de Ecologia de Comunidades/Formigas <http://www.labecol.ufv.br>
(31) 3899-4018 - Contato Skype: rrsolar
Universidade Federal de Viçosa - MG
==========================================

	[[alternative HTML version deleted]]


