[R] repeated measure one way anova
Peter Dalgaard
p.dalgaard at biostat.ku.dk
Tue Oct 28 08:58:00 CET 2008
Dieter Menne wrote:
> JohnLi <jli136 <at> site.uottawa.ca> writes:
>> I am a new comer for Statistics R. I am using R for one way repeated
>> measure anova, for example, on the following data consisting of three
>> groups.
>>
>>
>> c2 c3 c4
>> 85.83 75.86 84.19
>> 85.91 73.18 85.9
>
> -- Arrange your data in the "long form". Do it by hand, or use function pack, or
> reshape, or package reshape.
>
> (Assuming these are times. If these are categorical variables, better use
> strings as column descriptors)
>
>
>
> subj time conc (do not use t or c as variable name, these are
> "well-known functions" in R)
> A 2 85.83
> A 3 75.86
> A 4 84.19
> B 2 85.91
> ....
>
> Use package nlme, function lme. It might be a bit of an overkill for the simple
> case, but always worth the effort when things get more complex
>
> libary(nlme)
> summary(lme(c~time, random=~1|subj,data=mydata)
There is also anova.mlm:
d <- read.table("clipboard", header=T)
Y <- as.matrix(d)
fit1 <- lm(Y~1)
fit0 <- lm(Y~0)
anova(fit0, fit1, X=~1, test="Spherical")
anova(fit0, fit1, X=~1, test="Wilks")
--
O__ ---- Peter Dalgaard Øster Farimagsgade 5, Entr.B
c/ /'_ --- Dept. of Biostatistics PO Box 2099, 1014 Cph. K
(*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk) FAX: (+45) 35327907
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