On Nov 8, 2010, at 11:16 AM, Mitchell Maltenfort wrote:
Not with R,
Really?
require(sos)
findFn("power exact test")
found 54 matches; retrieving 3 pages
2 3
These look on point:
http://finzi.psych.upenn.edu/R/library/statmod/html/power.html
http://finzi.psych.upenn.edu/R/library/binom/html/cloglog.sample.size.html
Would also think that methods based on a poisson model of rare events
could be informative:
http://finzi.psych.upenn.edu/R/library/asypow/html/asypow.n.html
--
David.
but look for G*Power3, a free tool for power calc,
includes FIsher's test.
http://www.psycho.uni-duesseldorf.de/abteilungen/aap/gpower3
On Mon, Nov 8, 2010 at 10:52 AM, Giulio Di Giovanni
<perimessagg...@hotmail.com> wrote:
Hi,
I'm try to compute the minimum sample size needed to have at least
an 80% of power, with alpha=0.05. The problem is that empirical
proportions are really small: 0.00154 in one case and 0.00234.
These are the estimated failure proportion of two medical treatments.
Thomas and Conlon (1992) suggested Fisher's exact test and proposed
a computational method, which according to their table gives a
sample size of roughly 20000. Unfortunately I cannot find any
software applying their method.
-Does anyone know how to estimate sample size on Fisher's exact
test by using R?
-Even better, does anybody know other, maybe optimal, methods for
such a situation (small p1 and p2) and the corresponding R software?
Thanks in advance,
Giulio
David Winsemius, MD
West Hartford, CT
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