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st: Sample size


From   "Don Spady" <dspady@ualberta.ca>
To   "Statalist" <statalist@hsphsun2.harvard.edu>
Subject   st: Sample size
Date   Mon, 28 Apr 2003 09:18:30 -0600

Dear all
  I sent this before but got no response.  I have revised it.
I want to estimate the sample size needed to detect an disease that
occurs in 1 out of 1000 people (as an example).   The alternate
state is absence of disease which would occur in 999 of 1000 people on
average.   The problem is that I get numbers but I don't know if they
are the
right ones.  Can I use sampsi grp1 being those with disease and Grp2
being
those without disease.  Or do I use sampsi   0.001, onesample as in:

sampsi 0.001 0, p(0.8) onesample

I need help and thank in advance those that provide it.

Donald Spady
Dep't of Pediatrics, University of Alberta
(780) 407-1244

Nature has no reset button.

Donald Spady
Dep't of Pediatrics, University of Alberta
(780) 407-1244

Nature has no reset button.


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