[R] Power of t-test in R vs. S-PLUS
Alan T. Arnholt
arnholt at cs.appstate.edu
Fri Mar 1 22:14:36 CET 2002
Could someone shed some light on the statement from Thomas
that "(with sampling uncertainties of about +/- 2% in each
number)". What exactly is being said about the accuracy of
the simulation and how is that number +/-2% being
determined.
Thanks,
Alan
> So at 0.548882 there is about 80% power, at 0.4322771 there is about 55%
> power (with sampling uncertainties of about +/- 2% in each number).
>
>
> It is interesting to note that a simulation shows the unequal-variance
> t-test to have only 75% power at 0.5488882, indicating the sensitivity of
> the power calculations at this sample size.
>
> -thomas
>
> Thomas Lumley Asst. Professor, Biostatistics
> tlumley at u.washington.edu University of Washington, Seattle
----------------------
Alan T. Arnholt
Associate Professor
Department of Mathematical Sciences
Appalachian State University
Tel: (828) 262-2863
Fax: (828) 265-8617
http://www1.appstate.edu/~arnholta/
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