[R-sig-ME] comparing treatment with different skewness

Nicholas Lewin-Koh nikko at hailmail.net
Thu Mar 3 22:40:07 CET 2011

Hi Maarten,
Without the random effects, you are basically
asking can you fit a model where the variance is a function of the
So I would think you could do this using nlme,
ie somehthing like
lme(y~T + X1, data=mydat,

However, without more information it is hard to say more than that.


> Message: 2
> Date: Thu, 3 Mar 2011 11:11:51 +0100
> From: Maarten de Groot <Maarten.deGroot at nib.si>
> To: <r-sig-mixed-models at r-project.org>
> Subject: [R-sig-ME] comparing treatment with different skewness
> Message-ID: <4D6F6967.8010303 at nib.si>
> Content-Type: text/plain; charset="ISO-8859-1"; format=flowed
> Dear list,
> I have a problem regarding choosing the distribution family for a mixed 
> model. I want to compare my response variable y with treatment A,B,C and 
> D. In each of the treatments the distribution of y is differently. Is 
> there a way to implement this in a mixed model?
> Kind regards,
> Maarten

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