[R-sig-ME] problem using lmer with family = Gamma

[David Duffy]

On Fri, 11 Jun 2010, Rafael Mares wrote:

> Dear all
>
> I'm trying to run a GLMM with Gamma errors (as seems most appropriate
> for my data) using the lme4 package (version 0.999375-33)
>
> fullmod<-lmer(sniff ~ treatment + sex + domstatus + donor.age +
> (1|group/id), family = Gamma, REML = FALSE, data = pres)
>
> Error in mer_finalize(ans) : mu[i] must be positive: mu = -44.2351, i = 1

May I ask if you have fitted an ordinary GLM using the fixed effects? 
Have you perhaps tried a Box-Cox approach, or a LMM with log(sniff)?

Cheers, David Duffy.
-- 
| David Duffy (MBBS PhD)                                         ,-_|\
| email: davidD at qimr.edu.au  ph: INT+61+7+3362-0217 fax: -0101  /     *
| Epidemiology Unit, Queensland Institute of Medical Research   \_,-._/
| 300 Herston Rd, Brisbane, Queensland 4029, Australia  GPG 4D0B994A v