Mohammad AlMarzouq <koutbo6 <at> gmail.com> writes: > > 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. >
I'm surprised that you found evidence that tweedie could be used with lmer: in general, lmer only allows families that have been hard-coded (and doesn't allow families with "extra" parameters, such as negative binomial, beta-binomial, tweedie etc.). Perhaps you were reading about lme? Ben Bolker ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.