Dear list,I'm trying to fit this model with frequency data (values vary from 0 to 100).
a<-glmer(variable~factorA+(1|subject), family = poisson, data = endem)
In addition I'm trying to fit the same model with a quasi-poisson distribution
b<-glmmPQL(variable~factorA+(1|subject), family = quasipoisson, data = endem)
How can I asses for overdispersion of the data in order to use a or b model?
Moreover, if I add another fixed factor (factor B) and I'm primarily interested in both the effects of the factorA and the interaction between A and B (but I'm not interested in the effects of the factor B), how should I proceed?


                                                                                                                                
Ludovico
Frate

PhD student (University of Molise - Italy)
Environmetrics Lab
http://www.distat.unimol.it/STAT/environmetrica/organico/collaboratori/ludovico-frate-1
Department of Biosciences and Territory - DiBT
Università del Molise.
Contrada Fonte
Lappone, 
86090 -  Pesche (IS)
ITALIA.
Cel: ++39
3333767557
Fax: ++39 (0874) 404123
E-mail ludovico.frate@unimol.it
ludovicofrate@hotmail.it
 		 	   		  
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