Based on what you suggested I did the following:
1. Dataset$Sessn <- as.factor(Dataset$Sessn) 2. mod <- lm(cbind(Sessn=="1", Sessn=="2") ~ Trtmt, data=Dataset) 3. idata <- data.frame(Sessn=factor(1:2)) 4. Anova(mod, idata=idata, idesign=~Sessn)) ERROR: The error SSP matrix is apparently of deficient rank = 0 < 1 I have noticed that my DV (Response) is not in play in the coding above. Then I have modified it to: mod2 <- lm(*Response*~(cbind(Sessn=="1", Sessn=="2")) * Trtmt, data=Dataset) idata2 <- data.frame(Sessn=factor(1:2)) Anova(mod, idata=idata2, idesign=~Sessn) ERROR: The error SSP matrix is apparently of deficient rank = 0 < 1 Then I have modified it to: mod2 <- lm(Response~(cbind(Sessn=="1", Sessn=="2")) * Trtmt, data=Dataset) idata2 <- data.frame(Sessn=factor(1:2)) Anova(mod, idata=idata2, idesign=~*(cbind(Sessn=="1", Sessn=="2")) * Trtmt*) ERROR: object 'Trtmt' not found Then I have modified it to: mod2 <- lm(Response~(cbind(Sessn=="1", Sessn=="2")) * Trtmt, data=Dataset) idata2 <- data.frame(Sessn=factor(1:2)) Anova(mod, idata=idata2, idesign=~(cbind(Sessn=="1", Sessn=="2")) * * Dataset$Trtmt*) ERROR: variable lengths differ (found for 'Dataset$Trtmt') [THIS IS THE ERROR THAT I HAVE BEEN GETTING WITH MY ACTUAL DATASET FOLLOWING "CAR" PACKAGE RECOMMENDATIONS) Any idea what am I doing wrong? I have attached my mock data for convenience in csv. Sincerely, Sergios Charntikov (Sergey), MA Behavioral Neuropharmacology Lab Department of Psychology University of Nebraska-Lincoln Lincoln, NE 68588-0308 USA sergios...@gmail.com www.unl.edu/psychoneuropharm/ On Mon, Nov 9, 2009 at 12:33 PM, John Fox <j...@mcmaster.ca> wrote: > 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.