[R] P values
Frank E Harrell Jr
f.harrell at Vanderbilt.Edu
Tue May 11 23:56:02 CEST 2010
On 05/11/2010 04:50 PM, Bert Gunter wrote:
> Inline below.
> -- Bert
Bert - I disagree with you. You have understated the problems with
> Bert Gunter
> Genentech Nonclinical Statistics
> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On
> Behalf Of Greg Snow
> Sent: Tuesday, May 11, 2010 2:37 PM
> To: Bak Kuss; murdoch.duncan at gmail.com; jorismeys at gmail.com
> Cc: R-help at r-project.org
> Subject: Re: [R] P values
> " Small p-values indicate a hypothesis and data that are not very
> consistent and for small enough p-values we would rather disbelieve the
> hypothesis (though it may still be theoretically possible). "
> This is false.
> It is only true when the hypotheses are prespecified (not derived from
> looking at the data first), when there's only one being tested (not,say,
> 10,000), etc. etc.
> (Incidentally, "small enough" is not meaningful; making it so is usually
> IMHO far from being niggling details, these are the crux of the reason that
> the conventional use of P values to decide what is scientifically "valid"
> and what is not is a pox upon science. This is not an original view, of
> Don't want to stir up a hornet's nest, so feel free to silently dismiss. But
> contrary views are welcome, as always.
> No more from me on this -- I promise!
> -- Bert
> R-help at r-project.org mailing list
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
Frank E Harrell Jr Professor and Chairman School of Medicine
Department of Biostatistics Vanderbilt University
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