except for the R^2 symbol...I found that problem else where too, but have
no solution yet.
__
Thomas Szegvary
Institute of Environmental Geosciences
Department of Geosciences
University of Basel
Bernoullistrasse 30
CH - 4056 Basel
Tel. 41-61-267 04 82
Fax. 41-61-267 04 79
Email: t.szegvary at unibas.ch
www.radon.unibas.ch
www.unibas.ch/environment
-----Urspr?ngliche Nachricht-----
Von: Andrew Niccolai [mailto:andrew.niccolai at yale.edu]
Gesendet: Freitag, 20. Juli 2007 14:30
An: rob.robinson at bto.org; 'Thomas Szegvary'; r-sig-geo at stat.math.ethz.ch
Betreff: RE: [R-sig-Geo] Adding R-square to linear regression
I would merely add to Rob's reply that the text line can be modified to the
following:
text(x=2,y=2, paste("R squared = ", summary(c)$r.squared, sep=""))
Does anyone know the expression function that would produce an R squared
symbol? I tried expression(R^2) and that seems to only works correctly if
you have a follow on formula such as expression(x^2 == sum(over(x[i], n),
i==1, n). Any ideas?
Andrew Niccolai
Doctoral Candidate
Yale School of Forestry
-----Original Message-----
From: r-sig-geo-bounces at stat.math.ethz.ch
[mailto:r-sig-geo-bounces at stat.math.ethz.ch] On Behalf Of Rob Robinson
Sent: Friday, July 20, 2007 8:02 AM
To: 'Thomas Szegvary'; r-sig-geo at stat.math.ethz.ch
Subject: Re: [R-sig-Geo] Adding R-square to linear regression
Thomas,
Can you not use text() to add a label? If you are using lm() to generate
the regression you can get at the R.sq by calling summary:
summary(c)$r.squared [there's also an adj.r.squared, have a look at
summary.lm] So something along the lines of
text(x=xpos,y=ypos,summary(obj)$r.squared)
ought to work, see code below
Hth
rob
a=c(1,2,3,4,5)
b=c(1,3,2,5,4)
c=lm(a~b)
summary(c)$r.squared
plot(a~b)
text(x=2,y=2,summary(c)$r.squared)
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-----Original Message-----
From: r-sig-geo-bounces at stat.math.ethz.ch
[mailto:r-sig-geo-bounces at stat.math.ethz.ch] On Behalf Of Thomas
Szegvary
Sent: 20 July 2007 12:39
To: r-sig-geo at stat.math.ethz.ch
Subject: [R-sig-Geo] Adding R-square to linear regression
Dear R users
I want to produce scatter plots from the following data set, using R
2.5.0
summary(comps)
OBS TM5_STAND
Min. : 0.250 Min. : 4.223
1st Qu.: 2.440 1st Qu.: 5.539
Median : 3.936 Median : 6.449
Mean : 4.475 Mean : 6.748
3rd Qu.: 5.790 3rd Qu.: 7.637
Max. : 13.283 Max. :15.452
A simple scatter plot, where I added a linear regression.
Here is the code:
plot(comps$OBS,comps$TM5_STAND,xlab="observation",ylab="222-Rn
model",main="TM5_STAND")
abline(lm(comps$TM5_STAND ~ comps$OBS,data=comps))
But as i have to do this for a lot of datasets, I want to compare the
R-square and therefore would like to add the R-Square to the plot
automatically. I have checked faq and a lot of r-sig-geo messages but
haven't found a solution, for this I think trivial problem.
Does someone knows a code for this?
Many thanks
Thomas
__
Thomas Szegvary
Institute of Environmental Geosciences Department of Geosciences
University of Basel Bernoullistrasse 30 CH - 4056 Basel
Tel. 41-61-267 04 82
Fax. 41-61-267 04 79
Email: t.szegvary at unibas.ch
www.radon.unibas.ch
www.unibas.ch/environment