[R] ANOVA in Randomized-complete blocks design
January Weiner
january at uni-muenster.de
Fri Nov 3 02:16:43 CET 2006
Dear all,
I am trying to repeat an example from Sokal and Rohlfs "Biometry" --
Box 11.4, example of a randomized-complete-blocks experiment.
The data is fairly simple:
series genotype weight
1 pp 0.958
1 pb 0.985
1 bb 0.925
2 pp 0.971
2 pb 1.051
2 bb 0.952
3 pp 0.927
3 pb 0.891
3 bb 0.892
4 pp 0.971
4 pb 1.010
4 bb 0.955
The model used for ANOVA in the book is
Y_{ij} = \mu + \alpha_i + B_i + [(\alpha B)_{ij}] + \epsilon_{ij}
(I am not quite confident how to represent this model in R, see below)
The ANOVA table from S&R looks like this:
MSB series 3 0.021 0.007 10.23 **
MSA genotypes 2 0.010 0.005 6.97 *
MSE error 6 0.004 0.001
In R, I am using the following model (is this correct?)
aov.ob = aov( genotype ~ genotype + series )
However, my results are
Df Sum Sq Mean Sq F value Pr(>F)
series 3 0.0135867 0.0045289 6.6360 0.02469 *
genotype 2 0.0056732 0.0028366 4.1563 0.07367 .
Residuals 6 0.0040948 0.0006825
What am I doing wrong?
Regards,
January
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