I should have been more careful in my description. When I say there is a 100-fold difference in variance across labs, I mean that variance in fixed1 (the predictor) varies 100-fold across labs, not the variance in y is 100-fold difference across labs.
Can lme4 account for such variance differences? On Fri, Sep 17, 2010 at 6:43 PM, Johan Jackson <johan.h.jack...@gmail.com>wrote: > Hi all, > > I have major heterogeneity in variances across labs (100-fold). There is no > apparent variance heterogeneity across y-hat. By using lme4 in the following > way, am I accounting for the variance differences in labs?: > > lmer(y ~ fixed1 + covariates + (fixed1|labs)) > > I'm not sure that it is - I think it is only allowing the means (slopes > [conditional means] & intercepts) to differ between labs. If so, how does > one appropriately model such variances differences? > > Thank you in advance, > > JJ > [[alternative HTML version deleted]] ______________________________________________ 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.