Hello,
I have searched and failed for a program or script or method to
conduct a power analysis for a MANOVA. My interest is a fairly simple case
of 5 dependent variables and a single two-level categorical predictor
(though the categories aren't balanced).
If anybody happens to know of a script that will do this in R, I'd
love to know of it! Otherwise, I'll see about writing one myself.
What I currently see is this, from help.search("power"):
stats::power.anova.test
Power calculations for balanced one-way
analysis of variance tests
stats::power.prop.test
Power calculations two sample test for
proportions
stats::power.t.test Power calculations for one and two sample t
tests
Any references on power in MANOVA would also be helpful, though of
course I will do my own lit search for them myself.
Cordially,
Adam D. I. Kramer
Hi Adam, My (and, judging from previous traffic on R-help about power analyses, also some other people's) preferred approach is to simply simulate an effect size you would like to detect a couple of thousand times, run your proposed analysis and look how often you get significance. In your simple case, this should be quite easy. HTH, Stephan Adam D. I. Kramer schrieb:> Hello, > > I have searched and failed for a program or script or method to > conduct a power analysis for a MANOVA. My interest is a fairly simple case > of 5 dependent variables and a single two-level categorical predictor > (though the categories aren't balanced). > > If anybody happens to know of a script that will do this in R, I'd > love to know of it! Otherwise, I'll see about writing one myself. > > What I currently see is this, from help.search("power"): > > stats::power.anova.test > Power calculations for balanced one-way > analysis of variance tests > stats::power.prop.test > Power calculations two sample test for > proportions > stats::power.t.test Power calculations for one and two sample t > tests > > Any references on power in MANOVA would also be helpful, though of > course I will do my own lit search for them myself. > > Cordially, > Adam D. I. Kramer > > ______________________________________________ > R-help at r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide > http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. >
http://www.amazon.com/Statistical-Power-Analysis-Behavioral-Sciences/dp/0805802835 Cohen's book was in fact the basis for the "pwr" package at CRAN. And it does have a MANOVA power analysis, which was left out of the "pwr" package. On Mon, Jan 26, 2009 at 4:12 PM, Adam D. I. Kramer <adik at ilovebacon.org> wrote:> Hello, > > I have searched and failed for a program or script or method to > conduct a power analysis for a MANOVA. My interest is a fairly simple case > of 5 dependent variables and a single two-level categorical predictor > (though the categories aren't balanced). > > If anybody happens to know of a script that will do this in R, I'd > love to know of it! Otherwise, I'll see about writing one myself. > > What I currently see is this, from help.search("power"): > > stats::power.anova.test > Power calculations for balanced one-way > analysis of variance tests > stats::power.prop.test > Power calculations two sample test for > proportions > stats::power.t.test Power calculations for one and two sample t > tests > > Any references on power in MANOVA would also be helpful, though of > course I will do my own lit search for them myself. > > Cordially, > Adam D. I. Kramer > > ______________________________________________ > R-help at r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. >-- Due to the recession, requests for instant gratification will be deferred until arrears in scheduled gratification have been satisfied.