On 05/11/2010 04:50 PM, Bert Gunter wrote:
Inline below.
-- Bert
Bert - I disagree with you. You have understated the problems with
P-values :-)
Frank
Bert Gunter
Genentech Nonclinical Statistics
-----Original Message-----
From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On
Behalf Of Greg Snow
Sent: Tuesday, May 11, 2010 2:37 PM
To: Bak Kuss; murdoch.dun...@gmail.com; jorism...@gmail.com
Cc: R-help@r-project.org
Subject: Re: [R] P values
Bak,
...
" 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
impossible).
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
course.
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@r-project.org mailing list
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.
--
Frank E Harrell Jr Professor and Chairman School of Medicine
Department of Biostatistics Vanderbilt University
______________________________________________
R-help@r-project.org mailing list
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.