Re: [R] help_transformation

From: Moshe Olshansky <m_olshansky_at_yahoo.com>
Date: Wed, 25 Jun 2008 23:25:26 -0700 (PDT)


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.

> 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
> Fax : +41 (0) 44 823 53 15
> Email: lukas.indermaur_at_eawag.ch
> www.lukasindermaur.ch <http://www.lukasindermaur.ch/>
>
>
>
>
>
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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. Received on Thu 26 Jun 2008 - 06:32:11 GMT

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