Probably the best way of doing this is via simulation. Have a look at chapter 5 of:
Bolker, B. 2008. Ecological models and data in R. Princeton Univ. Press, Princeton, NJ. for an introduction and a bunch of examples. Joerg On Wed, Feb 20, 2013 at 5:49 AM, Chad Widmer <cw...@st-andrews.ac.uk> wrote: > Dear R/statistics wizards, > > > > This may be more of a statistics question than an R one, but I’m hoping > that someone has the time to help. I’ve already consulted a few local > statisticians and I’ve not yet received a clear answer. Before I start an > experiment I want to conduct an a priori power analysis test for a > Generalized Linear Model, family = poisson. The response variables will be > counts. I want to look at the effects of 5 temperatures and 3 salinities, > and their interaction in 15 different combinations (5 temperatures each > testing 3 different salinity levels). I am hoping to learn the power I > would achieve if I used a sample size of 18 in each of the combinations, > for a total sample size N = 270. > > > > Does such a power analysis exist? Can I just use a power analysis for a > linear model since the glm is an extension of that (which seems to make > sense), or maybe even one from a 2 way anova? Can someone show me the path > of righteousness in R, or point me in the right direction please? > > > > Thank you very much for your valuable time. > > Chad > > [[alternative HTML version deleted]] > > > ______________________________________________ > R-help@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. > ______________________________________________ R-help@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.
