[R] Rsquared for anova
Ben Bolker
bbolker at gmail.com
Mon Apr 18 15:12:14 CEST 2011
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.
> >
> > ______________________________________________
> > R-help <at> r-project.org mailing list
> > https://stat.ethz.ch/mailman/listinfo/r-help
> > 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
>
> B.513
> Prinsstraat 13
> 2000 Antwerp
> Belgium
> +32 3 265 41 25
>
More information about the R-help
mailing list