Re: st: RE: Binomial confidence intervals (more)

[Richard Goldstein <richgold@ix.netcom.com>]

I was on vacation last week, but want to insert my 1.5 cents anyway:

The Yates corrected chi-squared is an approximation to Fisher. As such it is 
not as good as Fisher's exact test.

It has the same "disadvantage" as Fisher -- it is "conservative".  I see no 
reason to ever use the Yates correction (unless you are all-of-a-sudden bereft 
of Fisher's exact test.

Rich Goldstein

Richard Williams wrote:


> At 08:14 AM 9/9/2004 -0500, FEIVESON, ALAN H. (AL) (JSC-SK) (NASA) wrote:
>
> > All this discussion about failure of binomial confidence intervals to 
> > give
> > "exact" coverage also applies to the Fisher "exact" test, whose actual 
> > level
> > (probability of rejecting the null hypothesis of equal proportions, 
> > when in
> > fact the proportions are equal) is usually less than the nominal level,
> > depending on the true proprtions. In the frequentist setting, it's the 
> > same
> > problem - there are only a finite number of possible outcomes.
> >
> > Al Feiveson
>
> I was wondering about that.  So, is there also a raging controversy over 
> whether some alternative to Fisher is superior, e.g. Yates correction 
> for continuity?  Like Nick Cox said in an earlier post, it sounds like 
> "exact" is more of a propaganda term than an accurate description of the 
> test.  (Kind of like saying you've got the "best" product on the market.)
>
> -------------------------------------------
> Richard Williams, Notre Dame Dept of Sociology
> OFFICE: (574)631-6668, (574)631-6463
> FAX:    (574)288-4373
> HOME:   (574)289-5227
> EMAIL:  Richard.A.Williams.5@ND.Edu
> WWW (personal):    http://www.nd.edu/~rwilliam
> WWW (department):    http://www.nd.edu/~soc
*
*   For searches and help try:
*   http://www.stata.com/support/faqs/res/findit.html
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/