check for missing values.
Tal
On Wed, Sep 23, 2009 at 3:27 PM, pompon <julien.pompon@agr.gc.ca> wrote:
>
> Hi,
>
> I am performing a repeated measures 2-way ANOVA to assess the influence of
> plant and leaf on aphid fecundity. Fecundity is measured for each aphid on
> a
> single leaf.
> Here is what I typed.
>
> wingless <- reshape(Wingless,
> varying >
>
list(c("d0","d1","d2","d3","d4","d5","d6","d7","d8","d9","d10","d11","d12","d13","d14","d15","d16")),
> v.names = c("fecundity"), timevar =
"time",
> direction = "long")
>
> wingless.aov <- aov(fecundity ~ factor(time) * clip.cage * plant +
> Error(factor(id)), data = wingless)
>
> summary(wingless.aov)
>
> and I obtained
>
> Error: factor(id)
> Df Sum Sq Mean Sq F value Pr(>F)
> factor(time) 4 56.789 14.197 3.0613 0.05925 .
> clip.cage 1 14.149 14.149 3.0509 0.10621
> plant 1 3.251 3.251 0.7010 0.41880
> factor(time):clip.cage 1 0.304 0.304 0.0655 0.80240
> clip.cage:plant 1 17.114 17.114 3.6903 0.07880 .
> Residuals 12 55.652 4.638
> ---
> Signif. codes: 0 '***' 0.001 '**' 0.01 '*' 0.05
'.' 0.1 ' ' 1
>
> Error: Within
> Df Sum Sq Mean Sq F value Pr(>F)
> factor(time) 16 340.83 21.30 11.5222 < 2e-16 ***
> factor(time):clip.cage 16 27.34 1.71 0.9242 0.54195
> factor(time):plant 16 46.36 2.90 1.5673 0.07783 .
> factor(time):clip.cage:plant 16 24.50 1.53 0.8281 0.65304
> Residuals 255 471.44 1.85
> ---
> Signif. codes: 0 '***' 0.001 '**' 0.01 '*' 0.05
'.' 0.1 ' ' 1
>
> I don't understand why I have the factor(time) inmy between subject
> results,
> whereas with a similar set of data I don't.
>
> Thank you very much,
> Julien Pompon.
> --
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>
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--
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