Dear Segios, For repeated-measures designs, the Anova() function requires a multivariate linear model fit to the "wide" version of the data set, in which each of the repeated measures appears as a separate variable. It is necessary that you have the same occasions observed for all subjects. For your scaled-down example, you'd have two response variables named, e.g., Sessn1 and Sessn2. Then you'd fit the multivariate linear model as mod <- lm(cbind(Sessn1, Sessn2) ~ Trtmnt, data=Dataset). The idata data frame could simply be idata <- data.frame(Sessn=factor(1:2)). Then you could get the MANOVA and repeated-measure ANOVA, including sphericity test, etc., as summary(Anova(mod, idata=idata, idesign=~Sessn)).
I hope this helps, John -------------------------------- John Fox Senator William McMaster Professor of Social Statistics Department of Sociology McMaster University Hamilton, Ontario, Canada web: socserv.mcmaster.ca/jfox > -----Original Message----- > From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On > Behalf Of Sergios (Sergey) Charntikov > Sent: November-09-09 1:18 PM > To: r-help@r-project.org > Subject: [R] Getting Sphericity Tests for Within Subject Repeated Measure > Anova (using "car" package) (Adjusted Dataset) > > [corrected dataset below] > > > Hello everyone, > > I am trying to do within subjects repeated measures anova followed by the > test of sphericity (sample dataset below). > I am able to get either mixed model or linear model anova and TukeyHSD, but > have no luck with Repeated-Measures Assuming Sphericity or Separate > Sphericity Tests. > I am trying to follow example from "car" package, but it seems that I am not > getting something right. > > > Dataset$Sessn <- as.factor(Dataset$Sessn) > > > LinearModel.1 <- lm(Response ~ Sessn*Trtmt, data=Dataset) > > > summary(LinearModel.1) > > All, good so far, but I have problem understanding "idata=" and "idesign=" > functions pertaining to my example. Session is my repeated measure (Sessn 1 > and Sessn 2 = two sessions, in reality I have more) and it is already > stacked. Any help or guidance on this matter. > > Thank you, my mock dataset is below. Each subject has two levels of > treatment throughout four calendar days which are recoded to Session 1 and > Session 2 in order to compare treatments by the first and subsequent days of > exposure (Treatment x Session; my DV is Response; Session is repeated). > > Subj Trtmt Sessn Response > 1 N 1 5 > 1 D 1 6 > 1 N 2 4 > 1 D 2 7 > 2 N 1 8 > 2 D 1 9 > 2 N 2 2 > 2 D 2 1 > 3 N 1 4 > 3 D 1 5 > 3 N 2 6 > 3 D 2 2 > 4 N 1 5 > 4 D 1 6 > 4 N 2 4 > 4 D 2 7 > 5 N 1 8 > 5 D 1 9 > 5 N 2 2 > 5 D 2 1 > 6 N 1 4 > 6 D 1 5 > 6 N 2 6 > 6 D 2 2 > > > > Sincerely, > > Sergios Charntikov (Sergey), MA > > Behavioral Neuropharmacology Lab > Department of Psychology > University of Nebraska-Lincoln > Lincoln, NE 68588-0308 USA > > sergioschr-at-gmail-dot-com > > [[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. ______________________________________________ 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.
