I have several plots where I'd like to add the formula from the linear model automatically, i.e. in form of y=ax+b, to the plot. I used lm() for a simple scatter plot. I was able to add the r-sqare to the plot, using summary(lm$r.square) to extract the value for r^2. but for the coefficients a and b I couldn't extract the values like for r-square. I can check the values using coef(lm), but to be able to write it as text to the plot I should extract the values, am I right? Or is there a better solution? Does anyone has an idea? I couldn't find any yet... Thanks a lot,Thomas __ Thomas Szegvary Institute of Environmental Geosciences Department of Geosciences University of Basel Bernoullistrasse 30 CH - 4056 Basel Tel. 41-61-267 04 82 Fax. 41-61-267 04 79 Email: t.szegvary at unibas.ch www.radon.unibas.ch www.unibas.ch/environment
Get lm formula
2 messages · Thomas Szegvary, ONKELINX, Thierry
You'll need something like
x <- rnorm(100)
y <- 0.5 * x + rnorm(100) + 1
fit <- lm(y ~x)
paste("y =", round(fit$coef[2], 2), "x +", round(fit$coef[1], 2))
Please note that this is R-sig-geo, the R mailing list dedicated to
spatial issues. For more general questions (like this one) you'll get
more respons from R-help (r-help at stat.math.ethz.ch).
Cheers,
Thierry
------------------------------------------------------------------------
----
ir. Thierry Onkelinx
Instituut voor natuur- en bosonderzoek / Research Institute for Nature
and Forest
Cel biometrie, methodologie en kwaliteitszorg / Section biometrics,
methodology and quality assurance
Gaverstraat 4
9500 Geraardsbergen
Belgium
tel. + 32 54/436 185
Thierry.Onkelinx at inbo.be
www.inbo.be
Do not put your faith in what statistics say until you have carefully
considered what they do not say. ~William W. Watt
A statistical analysis, properly conducted, is a delicate dissection of
uncertainties, a surgery of suppositions. ~M.J.Moroney
-----Oorspronkelijk bericht----- Van: r-sig-geo-bounces at stat.math.ethz.ch [mailto:r-sig-geo-bounces at stat.math.ethz.ch] Namens Thomas Szegvary Verzonden: maandag 23 juli 2007 16:33 Aan: r-sig-geo at stat.math.ethz.ch Onderwerp: [R-sig-Geo] Get lm formula I have several plots where I'd like to add the formula from the linear model automatically, i.e. in form of y=ax+b, to the plot. I used lm() for a simple scatter plot. I was able to add the r-sqare to the plot, using summary(lm$r.square) to extract the value for r^2. but for the coefficients a and b I couldn't extract the values like for r-square. I can check the values using coef(lm), but to be able to write it as text to the plot I should extract the values, am I right? Or is there a better solution? Does anyone has an idea? I couldn't find any yet... Thanks a lot,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
_______________________________________________ R-sig-Geo mailing list R-sig-Geo at stat.math.ethz.ch https://stat.ethz.ch/mailman/listinfo/r-sig-geo