[R] Syntax error in using Anova (car package)

[Fox, John]

Dear David,

Thanks for the correction.

I copied the link from the R Journal website at <https://journal.r-project.org/archive/RJournal.bib>, so I guess they need to fix their .bib file.

I'm cc'ing the R Journal editor.

Best,
 John



> -----Original Message-----
> From: David Winsemius [mailto:dwinsemius at comcast.net]
> Sent: Wednesday, November 25, 2015 12:52 PM
> To: Fox, John
> Cc: angelo.arcadi at virgilio.it; r-help at r-project.org
> Subject: Re: [R] Syntax error in using Anova (car package)
> 
> 
> > On Nov 25, 2015, at 9:23 AM, Fox, John <jfox at mcmaster.ca> wrote:
> >
> > Dear Angelo,
> >
> > I'm afraid that this is badly confused. To use Anova() for repeated
> measures, the data must be in "wide" format, with one row per subject.
> To see how this works, check out the OBrienKaiser example in ?Anova and
> ?OBrienKaiser, or for more detail, the R Journal paper at
> <{http://journal.r-project.org/archive/2013-1/RJournal_2013-1_fox-
> friendly-weisberg.pdf>.
> 
> I got an error with that link, but this link succeeded:
> 
> https://journal.r-project.org/archive/2013-1/fox-friendly-weisberg.pdf
> 
> 
> >
> > I hope this helps,
> > John
> >
> > -----------------------------------------------
> > John Fox, Professor
> > McMaster University
> > Hamilton, Ontario, Canada
> > http://socserv.socsci.mcmaster.ca/jfox/
> >
> >
> >
> >> -----Original Message-----
> >> From: angelo.arcadi at virgilio.it [mailto:angelo.arcadi at virgilio.it]
> >> Sent: Wednesday, November 25, 2015 11:30 AM
> >> To: r-help at r-project.org
> >> Cc: Fox, John
> >> Subject: Syntax error in using Anova (car package)
> >>
> >> Dear list members,
> >> I am getting an error while performing a repeated measures MANOVA
> using
> >> the Anova function
> >> of the "car" package. I want to apply it on the results of an
> experiment
> >> involving 19 participants,
> >> who were subjected to 36 stimuli, each stimulus was repeated twice
> for a
> >> total of 72 trials
> >> per subject. Participants had to adjust two parameters of sounds,
> >> Centroid and Sound_Level_Peak,
> >> for each stimulus. This is the head of my dataset (dependent
> variables:
> >> Centroid and
> >> Sound_Level_Peak; independent variables: Mat (6 levels) and Sh (2
> >> levels)).
> >>
> >>> head(scrd)
> >>    Subject         Mat   Sh      Centroid            Sound_Level_Peak
> >> 1     Subject1      C     DS        1960.2               -20.963
> >> 2     Subject1      C     SN        5317.2               -42.741
> >> 3     Subject1      G     DS       11256.0               -16.480
> >> 4     Subject1      G     SN        9560.3               -19.682
> >> 5     Subject1      M     DS        4414.1               -33.723
> >> 6     Subject1      M     SN        4946.1               -23.648
> >>
> >>
> >> Based on my understanding of the online material I found, this is the
> >> procedure I used:
> >>
> >> idata <- data.frame(scrd$Subject)
> >> mod.ok <- lm(cbind(Centroid,Sound_Level_Peak) ~  Mat*Sh,data=scrd)
> >> av.ok <- Anova(mod.ok, idata=idata, idesign=~scrd$Subject)
> >>
> >>
> >> I get the following error
> >>
> >> Error in check.imatrix(X.design) :
> >>  Terms in the intra-subject model matrix are not orthogonal.
> >>
> >>
> >> Can anyone please tell me what is wrong in my formulas?
> >>
> >> Thanks in advance
> >>
> >> Best regards
> >>
> >> Angelo
> >>
> >>
> >>
> >>
> >
> > ______________________________________________
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> 
> David Winsemius
> Alameda, CA, USA