Re: [R] normality test

From: Pieter Provoost <pieterprovoost_at_gmail.com>
Date: Fri 29 Apr 2005 - 00:52:08 EST

Thanks all for your comments and hints. I will try to keep them in mind. Since a number of people asked me what I'm trying to do: I want to apply Bayesian inference to a simple ecological model I wrote, and therefore I need to fit (uniform, normal or lognormal) distributions to sets of observed data (to derive mean and sd). You probably have noticed that I'm quite new to statistics, but I'm working on that...

Pieter

> On Thu, 28 Apr 2005 08:52:33 -0500 roger koenker wrote:
>
> > For my money, Frank's comment should go into fortunes. It seems a
> > rather Sisyphean battle to keep the lessons of robustness on the
> > statistical table but nevertheless well worthwhile.
>
> Added.
>
> On more comment: maybe it's also worth noting that you don't necessarily
> have to rank-transform the data. Instead you can also use a permutation
> test based on the original observations.
> <advertisment>
> This approach is implemented in the coin package for conditional

> inference.
> </advertisment>
>
> Z
>
>
> > url: www.econ.uiuc.edu/~roger Roger Koenker
> > email rkoenker@uiuc.edu Department of
> > Economics vox: 217-333-4558 University
> > of Illinois fax: 217-244-6678 Champaign,
> > IL 61820
> >
> > On Apr 28, 2005, at 7:46 AM, Frank E Harrell Jr wrote:
> >
> > >
> > > Usually (but not always) doing tests of normality reflect a lack of
> > > understanding of the power of rank tests, and an assumption of high
> > > power for the tests (qq plots don't always help with that because of
> > > their subjectivity). When possible it's good to choose a robust
> > > method. Also, doing pre-testing for normality can affect the type I
> > > error of the overall analysis.
> > >
> > > --
> > > Frank E Harrell Jr Professor and Chair School of
> > > Medicine
> > > Department of Biostatistics Vanderbilt
> > > University
> > >
> > > ______________________________________________
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>
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R-help@stat.math.ethz.ch mailing list
https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Fri Apr 29 01:00:15 2005

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