Message-ID: <loom.20110418T150328-233@post.gmane.org>
Date: 2011-04-18T13:12:14Z
From: Ben Bolker
Subject: Rsquared for anova
Dorien Herremans <dorien.herremans <at> ua.ac.be> writes:
>
> Thanks Dieter,
>
> Even if I use lm(), I get the following output:
>
> > summary(fit)
> ? ? ? ? ? ? ?Df ?Sum Sq Mean Sq F value ? ?Pr(>F)
> nh1 ? ? ? ? ? ?1 ? 324.0 ?323.99 ?139.13 < 2.2e-16 ***
> nh2 ? ? ? ? ? ?1 ? 723.1 ?723.12 ?310.53 < 2.2e-16 ***
> nh3 ? ? ? ? ? ?1 ?1794.2 1794.21 ?770.49 < 2.2e-16 ***
> Residuals ? 4604 10721.2 ? ?2.33
> ---
> Signif. codes: ?0 ?***? 0.001 ?**? 0.01 ?*? 0.05 ?.?
>
> no R squared to be found.
>
Really ??
When I run the example in ?lm I get:
> summary(lm.D9)
Call:
lm(formula = weight ~ group)
Residuals:
Min 1Q Median 3Q Max
-1.0710 -0.4938 0.0685 0.2462 1.3690
Coefficients:
Estimate Std. Error t value Pr(>|t|)
(Intercept) 5.0320 0.2202 22.850 9.55e-15 ***
groupTrt -0.3710 0.3114 -1.191 0.249
---
Signif. codes: 0 ?***? 0.001 ?**? 0.01 ?*? 0.05 ?.? 0.1 ? ? 1
Residual standard error: 0.6964 on 18 degrees of freedom
Multiple R-squared: 0.07308, Adjusted R-squared: 0.02158
F-statistic: 1.419 on 1 and 18 DF, p-value: 0.249
Note the last three lines. I would be shocked if there
weren't a similar set of information in your output ...
Your output looks like the result of summary(aov(...))
> Another strange thing. I did the same calculations in SPSS and got
> different results, among others, higher p values. lm() and aov() just
> do linear regressions (anova) right? I tried with the same factorial
> variables (without interaction effects to test).
There are a lot of things that could be different. Are
you treating factors (categorical predictors) as numeric by
accident?
>
> Thanks!
>
> On 15 April 2011 18:07, Dieter Menne <dieter.menne <at> menne-biomed.de> wrote:
> >
> > dorien wrote:
> >>
> >> I calculate an anova test in the following way:
> >>
> >> ... aov example
> >>
> >> I want to check the fit of the model with Rsquared
> >>
> >
> > Try summary(lm(...)) instead.
> >
> > Dieter
> >
> >
> >
> > --
> > View this message in context:
http://r.789695.n4.nabble.com/Rsquared-for-anova-tp3452399p3452434.html
> > Sent from the R help mailing list archive at Nabble.com.
> >
> > ______________________________________________
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> > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> > and provide commented, minimal, self-contained, reproducible code.
> >
>
> --
> Dorien Herremans
>
> Department of Environment, Technology and Technology Management
> Faculty of Applied Economics
> University of Antwerp
>
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>