Displaying 1 result from an estimated 1 matches for "zoop_2011".
2012 Dec 07
1
Negative Binomial GAMM - theta values and convergence
Hi there,
My question is about the 'theta' parameter in specification of a NB GAMM.
I have fit a GAM with an optimum structure of:
SB.gam4<-gam(count~offset(vol_offset)+
s(Depth_m, by=StnF, bs="cs")+StageF*RegionF,
family=negbin(1, link=log),
data=Zoop_2011[Zoop_2011$SpeciesF=='SB',])
However, this GAM shows heterogeneity in the residuals, and the model fit is not great. I would like to add a random effect to this GAM, for station (StnF), and a spatial correlation structure, for Depth_m. When trying to fit an equivalent GAMM to start with, I...