[R] prediction from glm

[Dieter Menne]

Hugues Santin-Janin <hsantin-janin <at> gct.org.uk> writes:

> I try to fit birds counts over years using glm. I have done (with Estate
> and year as factors):
> 
> Model1 <- glm(Females~Estate+Year+offset = log(area)), family =
> quasipoisson(link = log), na.action = "na.exclude") 
.. 
> Pred1 <- predict(Model1, type = "response", na.action = "na.exclude")
> 
> My question is: How can I obtain predictions for Females in each year
> that are standardized by averaging over the levels of Estate?

You should use the newdata argument in predict.glm to construct the "should-be" 
data set. The example on the page ?predict.glm creates budworm-data on the fly, 
but it's probably easier to understand if you create a separate data frame 
myfemales first, the do predict(Model1, newdata=myfemales,..) in a separate 
step.

Dieter Menne