I am working on similar stuff. I use aov(), I didn't use any package. And here's what I've been looking at http://www.gardenersown.co.uk/Education/Lectures/R/anova.htm http://www.personality-project.org/r/r.anova.html HTH On Sun, Dec 18, 2011 at 11:20 AM, David Winsemius <dwinsem...@comcast.net>wrote:
> > On Dec 17, 2011, at 9:42 PM, Junli wrote: > > Hi All, >> >> I am doing linear mixed model analysis for my multi-location >> experiment using R package "lme4". I just wonder whether I should >> check my data first to see whether they meet the three assumptions of >> ANOVA, that is, independence, >> > > Independence is not part of the data, but rather is a property that arises > from the design and conduct of the study. > > > normality and homogeneity. I saw a lot >> of examples and the manual of lme4, but no one did data check first. >> > > Perhaps because they know more about regression than you do? > > > In my experiment, the assumption of homogeneity usually cannot be met. >> I do not know whether it will affect the result a lot or not. >> > > I'm guessing that you are talking about homogeneity of variances or > homoschedasticity. I'm wondering how you propose to test that assumption > _before_ you construct a model? You should refer back to your text book to > see how this assumption was actually presented. If it tells you that one > can check for that assumption before the model is created, then toss that > book in the garbage. > > -- > > David Winsemius, MD > West Hartford, CT > > > ______________________________**________________ > R-help@r-project.org mailing list > https://stat.ethz.ch/mailman/**listinfo/r-help<https://stat.ethz.ch/mailman/listinfo/r-help> > PLEASE do read the posting guide http://www.R-project.org/** > posting-guide.html <http://www.R-project.org/posting-guide.html> > and provide commented, minimal, self-contained, reproducible code. > [[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.
