[R] help_transformation

[Moshe Olshansky]

Let F be the distribution function of Y, PSI the standard normal distribution anf IPSI it's inverse. Let f(x) = IPSI(F(x)). It is not difficult to see that f(Y) has standard normal distribution.
So you can replace F with the empirical distribution and IPSI is the qnorm function of R.


--- On Wed, 25/6/08, Indermaur Lukas <Lukas.Indermaur at eawag.ch> wrote:

> From: Indermaur Lukas <Lukas.Indermaur at eawag.ch>
> Subject: [R] help_transformation
> To: R-help at stat.math.ethz.ch
> Received: Wednesday, 25 June, 2008, 9:56 PM
> heya,
> i am fitting linear mixed effect model to a response Y. Y
> shows an s-shaped distribution when using QQ-plots (some
> zero values and some very high values). hence, which
> transformation should i apply that Y follows a normal
> distribution? any r-function/package available to do this?
>  
> thanks for any hint,
> regards,
> lukas
>  
>  
>  
> °°° 
> Lukas Indermaur, PhD student 
> eawag / Swiss Federal Institute of Aquatic Science and
> Technology 
> ECO - Department of Aquatic Ecology
> Überlandstrasse 133
> CH-8600 Dübendorf
> Switzerland
>  
> Phone: +41 (0) 71 220 38 25
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> Email: lukas.indermaur at eawag.ch
> www.lukasindermaur.ch <http://www.lukasindermaur.ch/>
> 
>  
>  
>  
> 
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