[R] Extracting F and p from aov() - tricksy solution

[Thomas Lumley]

On Tue, 22 May 2001, Mark Myatt wrote:

> Liqing Zhang <lzhang at ea.oac.uci.edu> writes:
> >
> >I performed an aov() analysis and got the following results:
> >
> >            Df Sum Sq Mean Sq F value Pr(>F)
> >block         1 0.0040  0.0040  0.3282 0.5672
> >Residuals   269 3.2766  0.0122
> >
> >Can anyone tell me how to extract the F value column and Pr(>F) column
> >from the summary output of aov analysis?
>

eg
data(warpbreaks)
LZ.aov <- summary(aov(breaks ~ wool + tension, data = warpbreaks))
as.data.frame(LZ.aov[[1]][,4:5])
             F value      Pr(>F)
wool        3.339316 0.073613669
tension     7.536651 0.001377778
Residuals         NA          NA


This is for an aov() with a single response. The complicated structure is
because you can have multiple responses, which would give a list of anova
tables as the summary.

	-thomas

Thomas Lumley			Asst. Professor, Biostatistics
tlumley at u.washington.edu	University of Washington, Seattle

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