[R] tweedie and lmer

[Mohammad AlMarzouq]

Hello all,

I have count data with about 36% of observations being zeros. I found  
in some of the examples of the r-help mail archives that a tweedie  
family of distributions could be used to fit a model with random  
effects. Upon installing the tweedie package and attempting to fit the  
following model:

lmer(SUS ~ 1 + (1| 
GRP),REML=FALSE,data=mydata,family=tweedie(var.power=1.55,link.power=0))

I get the following error:

Error in famType(glmFit$family) : unknown GLM family: ‘Tweedie’

If it helps, im on a mac with R V 2.9.1, lme4 V.0.999375-31, Tweedie  
V2.0.

Thanks,

Mohammad AlMarzouq