[R] looking for help on repeated measure ANOVA

Christian Jost jost at cict.fr
Thu Nov 28 20:31:05 CET 2002


I am new to R, therefore this might be a naive question, sorry in 
advance for that.

I have data on 4 groups of mice (#of subjects: 8,8,8,9) where the 
first group is the control group and 2-4 are 3 doses of a 
neuro-inhibitor. For each mouse we measured the exploration time of a 
familiar and a new object (thus repeated measure design), and I want 
to test whether there are different exploration times between 
'familiar' and 'new' and whether drug treatment has an effect on 
exploration plus the combined effect. Checking out the mailing list 
archives I found the helpful page by J. Baron on R in psychology and 
tried to adapt his example in chapter 6. Below you can find the 
result, and I simply wanted to ask some more experienced statistitian 
than me if I did the right thing with these data.

Thanks in advance, Christian.

souris.mat <- matrix(c(
54, 95,
45, 90,
19, 50,
21, 70,
13, 33,
33, 71,
52, 62,
46, 83,
16, 38,
34, 85,
23, 59,
40, 77,
26, 65,
16, 29,
36, 65,
41, 67,
52, 71,
34, 44,
73, 86,
43, 55,
34, 48,
40, 50,
34, 43,
35, 42,
60, 57,
38, 51,
55, 59,
59, 64,
38, 33,
38, 39,
39, 37,
54, 57,
38, 40), nrow = 33, byrow = T)

souris.mul <- cbind.data.frame(subj=1:33, 
dm=factor(rep(1:4,c(8,8,8,9))),souris.mat)
# dm = dose medicament

dimnames(souris.mul)[[2]] <- c("subj","dm","objFam","objNFam")
# objFam = objet familier, objNFam = objet non-familier

souris.uni <- data.frame(effect = as.vector(souris.mat),
subj = factor(paste("s",rep(1:33,2),sep="")),
dm = factor(paste("dm",rep(rep(1:4,c(8,8,8,9)),2), sep="")),
familier = factor(paste("fam",rep(1:2,c(33,33)),sep="")),
row.names = NULL)

resultat <- summary(aov(effect ~ dm * familier + Error(subj + subj:familier),
data = souris.uni))



-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-
r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html
Send "info", "help", or "[un]subscribe"
(in the "body", not the subject !)  To: r-help-request at stat.math.ethz.ch
_._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._



More information about the R-help mailing list