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st: Re: Power calculation for regression
There is a FAQ and a Stata Journal article on calculating power, both by Alan
Feiveson, which may be use.
Stata FAQ "How can I use Stata to calculate power by simulation?"
(http://www.stata.com/support/faqs/stat/power.html ) by Alan Feiveson
Stata Journal(2-2) "Power by simulation" by Alan Feiveson.
Hope this helps,
----- Original Message -----
From: "Wallace, John" <John_Wallace@affymetrix.com>
Sent: Monday, February 23, 2004 12:36 PM
Subject: st: Power calculation for regression
> Dear Statalisters
> I'm putting together a prospective protocol for a long term stability study
> (26 months) that will ultimately yield a series of 17 data points over time.
> Each data point will be an average of 5 replicates from a test. I
> anticipate plotting a regression of average intensity (the test result)over
> time, to yield a linear equation. Is there a common test for inferring an
> effect due to time, such as rejecting a null hypothesis of slope=0? Can I
> calculate power? Are five replicates at each point sufficient?
> Thanks for any guidance - even if its RTFM (though a pointer to a specific
> section would be appreciated - the help file for -regress- is dizzyingly
> John Wallace | Research Associate | Test Method Development
> AFFYMETRIX, INC. | 3380 Central Expressway | Santa Clara, CA 95051 | Tel:
> 408-731-5574 | Fax: 408-481-0435
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