[R] How to extract numbers from ANOVA tables?

[John Fox]

Dear Lars,

In addition to looking at the relevant help pages, a nice thing about R is
that the objects are there for you to examine. For example:

> mod <- lm(mpg ~ ., data=mtcars)
> av <- anova(mod)

> names(av)
[1] "Df"      "Sum Sq"  "Mean Sq" "F value" "Pr(>F)" 

> str(av)
Classes 'anova' and 'data.frame':       11 obs. of  5 variables:
 $ Df     : int  1 1 1 1 1 1 1 1 1 1 ...
 $ Sum Sq : num  817.71  37.59   9.37  16.47  77.48 ...
 $ Mean Sq: num  817.71  37.59   9.37  16.47  77.48 ...
 $ F value: num  116.42   5.35   1.33   2.34  11.03 ...
 $ Pr(>F) : num  5.03e-10 3.09e-02 2.61e-01 1.41e-01 3.24e-03 ...
 - attr(*, "heading")= chr  "Analysis of Variance Table\n" "Response: mpg"

Thus, e.g., av$"Sum Sq" returns the sums of squares:

> av$"Sum Sq"
 [1] 817.7129524  37.5939529   9.3709293  16.4674349  77.4757948   3.9493082
 [7]   0.1297687  14.4742372   0.9717105   0.4066688 147.4944300

You could do the same thing with the object returned by summary().

I hope that this helps,
 John

--------------------------------
John Fox, Professor
Department of Sociology
McMaster University
Hamilton, Ontario
Canada L8S 4M4
905-525-9140x23604
http://socserv.mcmaster.ca/jfox 
-------------------------------- 

> -----Original Message-----
> From: r-help-bounces at r-project.org 
> [mailto:r-help-bounces at r-project.org] On Behalf Of Brinkmann, Lars
> Sent: Saturday, December 08, 2007 4:09 AM
> To: r-help at stat.math.ethz.ch
> Subject: [R] How to extract numbers from ANOVA tables?
> 
> I need to extract numbers (eg. estimates, standard errors 
> etc.) summarized in an ANOVA table or summary() table for 
> further calculations. Can somebody help me or refer me to the 
> needed resource on the web?
> 
> 	[[alternative HTML version deleted]]
> 
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