regression coefficient for different factors
?summary produces r^2 in 2nd to last line, as in,
set.seed(12); a=rnorm(100); b = runif(100); c = factor(rep(c('No',
'Yes'),50)); df = data.frame(a,b,c)
head(df)
a b c 1 -1.4805676 0.9729927 No 2 1.5771695 0.2172974 Yes 3 -0.9567445 0.5205087 No 4 -0.9200052 0.8279428 Yes 5 -1.9976421 0.9641110 No 6 -0.2722960 0.6318801 Yes
mod = lm(a ~ b*c) summary(mod)
Call:
lm(formula = a ~ b * c)
Residuals:
Min 1Q Median 3Q Max
-1.8196 -0.4754 -0.0246 0.5585 2.0941
Coefficients:
Estimate Std. Error t value Pr(>|t|)
(Intercept) 0.2293 0.2314 0.991 0.324
b -0.4226 0.3885 -1.088 0.280
cYes 0.1578 0.3202 0.493 0.623
b:cYes -0.5878 0.5621 -1.046 0.298
Residual standard error: 0.8455 on 96 degrees of freedom
Multiple R-squared: 0.07385, Adjusted R-squared: 0.04491
F-statistic: 2.552 on 3 and 96 DF, p-value: 0.0601
------------------------------------------
Robert W. Baer, Ph.D.
Professor of Physiology
Kirksville College of Osteopathic Medicine
A. T. Still University of Health Sciences
800 W. Jefferson St.
Kirksville, MO 63501
660-626-2322
FAX 660-626-2965
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From: "Francesco Nutini" <nutini.francesco at gmail.com>
Sent: Friday, May 20, 2011 4:17 AM
To: "[R] help" <r-help at r-project.org>
Subject: [R] [r] regression coefficient for different factors
Dear R-helpers, In my dataset I have two continuous variable (A and B) and one factor. I'm investigating the regression between the two variables usign the command lm(A ~ B, ...) but now I want to know the regression coefficient (r2) of A vs. B for every factors. I know that I can obtain this information with excel, but the factor have 68 levels...maybe [r] have a useful command. Thanks, Francesco Nutini [[alternative HTML version deleted]]
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