[R-sig-ME] Split-plot Design

[Kevin Wright]

Your question is not very clear, but if you are trying to match the
results in Kuehl, you need a fixed-effects model:

dat <- read.table("expl14-1.txt", header=TRUE)
dat$block <- factor(dat$block)
dat$nitro <- factor(dat$nitro)
dat$thatch <- factor(dat$thatch)

colnames(dat) <- c("block","nitro","thatch","chlor")
m1 <- aov(chlor~nitro*thatch+Error(block/nitro), data=dat)
summary(m1)

Mixed-effects models and degrees of freedom have been discussed many
times on this list....search the archives.

K Wright


On Thu, Mar 20, 2008 at 12:39 PM,  <marcioestat at pop.com.br> wrote:
>
>
>
>  Hi listers,
>
>  I've been studying anova and at the book of Kuehl at the chapter
>  about split-plot there is a experiment with the results... I am trying to
>  understand the experiments and make the code in order to obtain the
>  results... But there is something that I didn't understand yet...
>  I have a split-plot design (2 blocks) with two facteurs, one
>  facteur has 4 treatments and the other facteur is a measure
>  taken in three years...
>  I organize my data set as:
>
>  Nitro Bloc Year Measure
>  a
>  x
>  1         3.8
>  a
>   x
>  2         3.9
>  a         x         3         2.0
>  a         y         1         3.7
>  a         y         2
>  2.4
>  a         y         3
>  1.2
>  b         x
>   1         4.0
>  b         x
>  2         2.5
>  and so on...
>
>
>  So, I am trying this code, because I want to test each factor and the
>  interaction...
>  lme=lme(measure ~ bloc + nitro + bloc*nitro, random= ~ 1|year,
>  data=lme)
>  summary(lme)
>  The results that I am obtaining are not correct, because
>  I calculated the degrees of fredom and they are not
>  correct... According to this design I will get two errors one for the
>  whole plot and other for the subplot....
>
>  Well, as I told you, I am still learning... Any suggestions...
>
>  Thanks in advance,
>
>  Ribeiro
>
>
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>
>
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