Dear Paul, I noticed a typo in my response and some poor formatting in the email message; please see below:
> -----Original Message----- > From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On > Behalf Of John Fox > Sent: January-29-09 9:23 PM > To: 'pgseye' > Cc: r-help@r-project.org > Subject: Re: [R] Q about how to use Anova.mlm > > Dear Paul, > > First, to fit a multivariate linear model to your data, you'll have to > rearrange the data from "long" format (with one observation per replicate) > to "wide" format (with one observation per subject). If your data are in the > data frame Data, then you'd do something like: > > Wide <- reshape(Data, v.names="Angle", idvar="Subject", timevar="Replicate", > direction="wide") > > Then, with the data in wide format, fit a multivariate linear model with > just a constant: > > mod <- lm(cbind(Angle.1, Angle.2, Angle.3, Angle.4, Angle.5, Angle.6) ~ 1, > data=DavisThin) The data argument should be data=Wide (I adapted the code from an example I already had and neglected to change the argument). > > Finally, use Anova() to get the tests: > > idata <- data.frame(Replicate=c("Angle.1", "Angle.2", "Angle.3", "Angle.4", > "Angle.5", "Angle.6")) > summary(Anova(mod, idata=idata, idesign=~Replicate)) Note that this is indeed two separate commands; they were apparently run together by my mailer. Regards, John > > If I understand correctly what you want, this should give it to you. > > As well, since your design has no between-subject factors and only a single > within-subject factor, you could also use anova() [i.e., anova.mlm()] to get > the same results. > > I hope this helps, > John > > ------------------------------ > John Fox, Professor > 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 pgseye > > Sent: January-29-09 7:40 PM > > To: r-help@r-project.org > > Subject: [R] Q about how to use Anova.mlm > > > > > > Hi, > > > > Am newish to stats and R, so I certainly appreciate any help. Basically I > > have 50 inidividuals whom I have 6 photos each of their optic nerve head. > I > > want to check that the orientation of the nerve head is consistent, ie the > 6 > > replicates show minimal or preferably no rotation differences. I'll draw > an > > arbitrary line between some blood vessels (same reference in each set of > > replicates) and determine an angle of deviation from the vertical and that > > angle will be my dependent variable. > > > > Subject Replicate Angle of Deviation > > 1 1 x > > 1 2 x > > 1 3 x > > 1 4 x > > 1 5 x > > 1 6 x > > 2 1 x > > 2 2 x > > 2 3 x > > 2 4 x > > 2 5 x > > 2 6 x > > etc > > > > I'm wanting to test for Sphericity (because I've read that you should - is > > this routine in a repeated measures ANOVA?) and can see that Anova.mlm in > > the CAR package offers this in addition to the alternative Greenhouse and > > Feldt tests. > > > > I just don't really know how to perform the test - can someone give me > some > > help. > > > > Thank you. > > > > Paul > > > > Dept of Ophthalmology > > Uni Melbourne, Australia > > -- > > View this message in context: http://www.nabble.com/Q-about-how-to-use- > > Anova.mlm-tp21739443p21739443.html > > Sent from the R help mailing list archive at Nabble.com. > > > > ______________________________________________ > > 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. ______________________________________________ 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.
