Matias,

The offset term is processed as part of parsing the formula, which results
in a vector of length of the response. Using a vector should not be a
problem.

Peter

--
Péter Sólymos, Dept Biol Sci, Univ Alberta, T6G 2E9, Canada AB
solymos@ualberta.ca, Ph 780.492.8534, http://psolymos.github.com
Alberta Biodiversity Monitoring Institute, http://www.abmi.ca
Boreal Avian Modelling Project, http://www.borealbirds.ca


On Fri, Jun 14, 2013 at 4:39 AM, Matias Ledesma <matutetote@hotmail.com>wrote:

> Hi,
>
> I have a question about the offset function in glm.nb. As I understod it
> is possible to use rates in the respons variable in glm.nb with the
> function offset.
>
> My model, modelA1F<-glm.nb(Tot.dameggs~STATN+offset(log(FECUND)))
>
> Tot.dameggs= total amount of damaged embryos per individual
> STATN= Station
> FECUND= total number of embryos per individual (huge varability)
>
> My question is if it is possible in this case when FECUND isnt the same
> for all individuals.
>
> Thanks
> /Matias
>
>
>
>
>
>
>
>
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