[R] Wrong results from anova

[Michael Dewey]

See in-line

On 14/04/2015 18:23, li li wrote:
> Hi all,
>    I have following data. When I perform an anova, the residual sum of
> square returns to be zero.
> But this is wrong, since we can hand calculate the RSS to be around 0.0308.
>    Did anyone come across the same problem before? Any suggestions?
>    Thanks.
>      Hanna
>
>> ydata
>          Y sample.Y
> 1   0.477      0.5
> 2   0.477      0.5
> 3   0.478      0.5
> 4  27.320       27
> 5  27.420       27
> 6  27.300       27
> 7  29.440       29
> 8  29.620       29
> 9  29.610       29
> 10 35.840       35
> 11 35.900       35
> 12 35.850       35
>> fit.Y <- aov(Y~sample.Y, data=ydata)
>> summary(fit.Y)
>              Df Sum Sq Mean Sq F value Pr(>F)
> sample.Y     3   2203   734.2  190706 <2e-16 ***
> Residuals    8      0     0.0
> ---
> Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1
>

  734.2 / 197096
[1] 0.003725088

Did you mean 0.0038 above?
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-- 
Michael
http://www.dewey.myzen.co.uk/home.html