From: <markleeds_at_verizon.net>

Date: Sat, 21 Mar 2009 22:51:18 -0500 (CDT)

R-help_at_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. Received on Sun 22 Mar 2009 - 02:55:58 GMT

Date: Sat, 21 Mar 2009 22:51:18 -0500 (CDT)

thanks ben: i think my example makes sense but my terminology of one
tailed two tailed was wrong or flipped or whatever. in fact, that's
why i gave the example. i wasn't remembering the terminology because
it's been too long since i stepped in a classroom ( 8 years ).

On Sat, Mar 21, 2009 at 10:42 PM, Ben Bolker wrote:

> <markleeds <at> verizon.net> writes:

*>
**>>
**>> by definition, the one tailed p-value has to be <= 0.5 so there is
**>> still something wrong with your OpenEpi calc. Most likely it's
**>> calculating the
**>> 2 tailed p-value and then mistakenly multiplying by 2. For example:
**>
**> For what it's worth, Fisher's exact test with alternative="greater"
**> (true odds ratio is > 1) does give 0.6273 in R. (Why does a one-tailed
**> test have to have p<=0.5? The probability that a test statistic
**> is greater than some null-hypothesis value can be anywhere
**> between 0 and 1 ...) It is a 1-tailed test,
**> but (as has been pointed out) multiplying it by 2 without
**> truncating at 1 is wrong.
**>
**> Ben Bolker
**>
**> ______________________________________________
**> R-help_at_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.
*

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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 Sun 22 Mar 2009 - 02:55:58 GMT

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