On Mar 5, 2008, at 12:03 AM, Will Holcomb wrote: > I have been trying to figure out how to run a simple simulation of > the ANOVA > and I'm coming up just a bit short. The code I've got is: > > cohen.f = .25 > groups = 4 > between.var = 19 > within.var = between.var / cohen.f ^ 2 > n = 500 > sim.means = rnorm(n = groups, mean = 0, sd = sqrt(between.var)) > sim.data = lapply(sim.means, function(mean) rnorm(n = n, mean = > mean, sd = > sqrt(within.var))) > sim.anova = ? > > I'm pretty sure I've got data with the between group and within group > variances that I want. I don't really know how to run an ANOVA on > it though. > All the examples I've been able to find (with aov and anova) > require an > explicit model. The ANOVA just tests the equivalence of means for a > set of > groups, right? Can I not just tell it to give me the likelihood the > means > are equal for all the columns without writing an explicit model.
I don't know if you can without writing an explicit model or not, but writing the model isn't that hard: simdata2 <- do.call(data.frame, sim.data) names(simdata2) <- LETTERS[1:4] simdata3 <- stack(simdata2) fit <- lm(values~ind, data=simdata3) summary(fit) anova(fit) Unless I misunderstood what you wanted to do. > Any help would be appreciated, > Will Haris Skiadas Department of Mathematics and Computer Science Hanover College ______________________________________________ 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.