On Thu, 22 Feb 2007, Aalim Weljie wrote: > Hello, > > I had a couple questions about manova modeling in R. > > I have calculated a manova model, and generated a summary.manova output > using both the Wilks test and Pillai test. > > The output is essentially the same, except that the Wilks lambda = 1 - > Pillai. Is this normal? (The output from both is appended below.)
For a 1-df test, yes: all the statistics give the same test (as ?summary.manova does say). > My other question is about the use of MANOVA. If I have one variable which > has a higher F-stat value (~60) than the MANOVA fstat (~20), but the other > 15 variables all have lower ANOVA F-stat values (~5-10), am I still okay in > using the MANOVA? (If I remove the one highly significant variable, the > MANOVA f-stat is still larger than the other univariate F-stats). OK for what purpose? Using (M)ANOVA for variable selection has many issues. > Thanks very much for your help, > > Aalim > > Output from Manova tests: > >> summary.manova(fit) > Df Pillai approx F num Df den Df Pr(>F) > response 1 0.9725 19.8967 16 9 4.193e-05 *** > Residuals 24 > --- > Signif. codes: 0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1 >> summary.manova(fit, test="Wilks") > Df Wilks approx F num Df den Df Pr(>F) > response 1 0.0275 19.8967 16 9 4.193e-05 *** > Residuals 24 > --- > Signif. codes: 0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1 > > [[alternative HTML version deleted]] > > ______________________________________________ > [email protected] 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. > -- Brian D. Ripley, [EMAIL PROTECTED] Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272866 (PA) Oxford OX1 3TG, UK Fax: +44 1865 272595 ______________________________________________ [email protected] 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.
