Maybe you want summary(aov(Y ~ A + Error(A:B)))
Kevin On Fri, Oct 30, 2015 at 9:32 AM, Wagenaar, Daniel (wagenadl) < wagen...@ucmail.uc.edu> wrote: > Dear R users: > > All textbook references that I consult say that in a nested ANOVA (e.g., > A/B), the F statistic for factor A should be calculated as F_A = MS_A / > MS_(B within A). But when I run this simple example: > > set.seed(1) > A = factor(rep(1:3, each=4)) > B = factor(rep(1:2, 3, each=2)) > Y = rnorm(12) > anova(lm(Y ~ A/B)) > > I get this result: > > Analysis of Variance Table > > Response: Y > Df Sum Sq Mean Sq F value Pr(>F) > A 2 0.4735 0.23675 0.2845 0.7620 > A:B 3 1.7635 0.58783 0.7064 0.5823 > Residuals 6 4.9931 0.83218 > > Evidently, R calculates the F value for A as MS_A / MS_Residuals. While it > is straightforward enough to calculate what I think is the correct result > from the table, I am surprised that R doesn't give me that answer directly. > Does anybody know if R's behavior is intentional, and if so, why? And, > perhaps most importantly, how to get the "textbook" result in the most > straightforward way? (I'd like to be able to give me students a simple > procedure...) > > Thanks, > > Daniel Wagenaar > > -- > Daniel A. Wagenaar, PhD > Assistant Professor > Department of Biological Sciences > McMicken College of Arts and Sciences > University of Cincinnati > Cincinnati, OH 45221 > Phone: +1 (513) 556-9757 > Email: daniel.wagen...@uc.edu > Web: http://www.danielwagenaar.net > ______________________________________________ > R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see > 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. > -- Kevin Wright [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see 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.
