[R-sig-ME] FW: linear mixed model for non-normal negative andcontinous dataa

[Titus von der Malsburg]

On 2014-04-28 Mon 12:31, Caroline Lustenberger <caroline.lustenberger at hotmail.com> wrote:
> mod_Knmn<-lmer(Knmn~Group*Timepoint+(1|VPnr),data=data)
>  
> When performing a qq-plot my residuals are clearly deviant from the
> norm (long-tailed). Due to negative values I cannot perform classical
> transformation methods (e.g. log transformation). How could I proccede
> with this data. Is there a possibility to use a generalized linear
> model?

Just multiply with -1 (turning the measurements into strictly positive
values) and then do a log transform or box-cox transform.

  Titus