See the acepack package or the transace function in Hmisc for ACE or AVAS.

-- Bert

On Thu, Nov 3, 2011 at 8:55 AM, Johannes Radinger <JRadinger@gmx.at> wrote:

> Hello,
>
> I am doing a simple regression using lm(Y~X).
> As my response and my predictor seemed to be skewed
> and I can't meet the model assumptions. Therefore
> I need to transform my variables.
>
> I wanted to ask what is the preferred way to find out
> if predictor and/or response needs to be transformed
> and if yes how (log-transform?).
>
> I found a procedure in "A modern approach to Regressoin
> in R" (Sheather, 2009): There they suggest an approach
> with the function bctrans from alr3...but it seems that it
> is deprecated. So what is the best way (box-cox test) find the best
> transformation for predictor and response simultaneously?
> AFAIK boxcox from MASS is used only used for transformation
> of the predictor?
>
> Thank you very much
> Johannes
>
> --
>
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> and provide commented, minimal, self-contained, reproducible code.
>



-- 

Bert Gunter
Genentech Nonclinical Biostatistics

Internal Contact Info:
Phone: 467-7374
Website:
http://pharmadevelopment.roche.com/index/pdb/pdb-functional-groups/pdb-biostatistics/pdb-ncb-home.htm

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