Dear all, I'm a beginner of R and I need to carry out some three-way mixed ANOVAs. Following examples at http://personality-project.org/r/r.anova.html, I managed to get the ANOVA part, but I don't know how can I check data normality and homogeneity of variance in R (since they're the required assumptions of ANOVA analysis). Are there any special command/packages? Could anyone give me some pointers/examples? Best regards, Haiyang -- Haiyang AI, Ph.D. student Department of Applied Linguistics The Pennsylvania State University [[alternative HTML version deleted]]
Schalk Heunis
2010-Jan-05 04:47 UTC
[R] Checking for normality and homogeneity of variance
For normality check out: ?shapiro.test HTH! Schalk On Tue, Jan 5, 2010 at 5:32 AM, Haiyang AI <aihaiyang@gmail.com> wrote:> Dear all, > > I'm a beginner of R and I need to carry out some three-way mixed ANOVAs. > Following examples at http://personality-project.org/r/r.anova.html, I > managed to get the ANOVA part, but I don't know how can I check data > normality and homogeneity of variance in R (since they're the required > assumptions of ANOVA analysis). > > Are there any special command/packages? Could anyone give me some > pointers/examples? > > Best regards, > Haiyang > > -- > Haiyang AI, Ph.D. student > Department of Applied Linguistics > The Pennsylvania State University > > [[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. >[[alternative HTML version deleted]]
Haiyang AI wrote:> > Dear all, > > I'm a beginner of R and I need to carry out some three-way mixed ANOVAs. > Following examples at http://personality-project.org/r/r.anova.html, I > managed to get the ANOVA part, but I don't know how can I check data > normality and homogeneity of variance in R (since they're the required > assumptions of ANOVA analysis). > >No..normality and homogeneity of the data it is not an assumption! It is normality and homogeneity of the residuals! See also: http://www3.interscience.wiley.com/cgi-bin/fulltext/122683826/PDFSTART Alain ----- Dr. Alain F. Zuur First author of: 1. Analysing Ecological Data (2007). Zuur, AF, Ieno, EN and Smith, GM. Springer. 680 p. URL: www.springer.com/0-387-45967-7 2. Mixed effects models and extensions in ecology with R. (2009). Zuur, AF, Ieno, EN, Walker, N, Saveliev, AA, and Smith, GM. Springer. http://www.springer.com/life+sci/ecology/book/978-0-387-87457-9 3. A Beginner's Guide to R (2009). Zuur, AF, Ieno, EN, Meesters, EHWG. Springer http://www.springer.com/statistics/computational/book/978-0-387-93836-3 Other books: http://www.highstat.com/books.htm Statistical consultancy, courses, data analysis and software Highland Statistics Ltd. 6 Laverock road UK - AB41 6FN Newburgh Tel: 0044 1358 788177 Email: highstat at highstat.com URL: www.highstat.com URL: www.brodgar.com -- View this message in context: http://n4.nabble.com/Checking-for-normality-and-homogeneity-of-variance-tp998821p998923.html Sent from the R help mailing list archive at Nabble.com.