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Re: st: RE: -sampsi- command and exact tests


From   Joseph Coveney <jcoveney@bigplanet.com>
To   Statalist <statalist@hsphsun2.harvard.edu>
Subject   Re: st: RE: -sampsi- command and exact tests
Date   Thu, 03 Feb 2005 11:12:27 +0900

Yulia Marchenko wrote:

[Abridged]

Sample size = 613 Exact power:.9131
Sample size = 610 Exact power:.9159
Sample size = 580 Exact power:.9001

The above results support the guess about other packages reporting sample
size for one-sided test.

-------------------------------------------------------------------------------

That was my guess, too.  But the decrease in power with the increase in sample 
size from 610 to 613 reminds of an alternative guess:  have you considered that 
the other packages might be using a different exact confidence interval to 
invert, such as the Blyth-Still-Cassela (StatXact) or the Blaker (S-Plus)?  

I implemented the latter in a do-file for a one-off use last year.  If I can 
get time to dig through my CD-R/W collection and find it to polish it into an 
ado-file, I'll try to post it.  The Blaker confidence interval begs the 
question of sidedness.

Joseph Coveney


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