[R-sig-ME] Logistic regression with factorial effect

[David Duffy]

On Thu, 18 Nov 2010, Billy wrote:

> Hello,
>
> I?d like to evaluate the temporal effect on the relationship between a
> continuous variable (e.g. size) and the probability of mate success.
>
> glm(success1 ~ size, family=binomial) -> test1.1
> glmer(success1 ~ size + (1|ind), family=binomial) -> test2.1
> glmer(success1 ~ size + month + (1|ind), family=binomial) -> test3.1
> glmer(success1 ~ size : month + (1|ind), family=binomial) -> test4.1
>
> However, the expected result is not observed in the output of all these
> models. Using a model selection approach and comparing the AIC values of all
> models, it seems that test1.1 model is the most likely.

You have kind of done something wrong.  Consider

m0: success ~ size + month + size:month [in R, size*month]
m1: success ~ size:month


Cheers, David Duffy.