File:Simpson's Paradox Continuous.svg
Example of the quantitative version of w:Simpson's paradox.
The graphic was created by User:Schutz for Wikipedia on 14 June 2007, using the R statistical project. The program that generated and exported the graphic is given below; the uploaded version was generated slightly differently to workaround a bug during the PS to SVG conversion with pstoedit command. The layout was slightly modified using Inkscape before upload.
x1 <- c(1,2,3,4) y1 <- x1 + 5 x2 <- x1 + 7 y2 <- x2 - 7 x <- c(x1,x2) y <- c(y1,y2) postscript("simpson.eps", paper="special", width=4.5, height=3) par(las=1) par(mar=c(3,3,0.5,0.5)) par(mgp=c(2,1,0)) plot(x,y, cex=2, pch=21, col=rep(c("blue", "red"), each=4), bg=rep(c("lightblue", "pink"), each=4), xlim=range(x)+c(-2,2), ylim=range(y)+c(-2,2)) abline(lm(y1 ~ x1), col="blue", lwd=2) abline(lm(y2 ~ x2), col="red", lwd=2) abline(lm(y ~ x), lwd=2, lty=2) dev.off()
Licensing
This work has been released into the public domain by its author, I, Schutz. This applies worldwide. In some countries this may not be legally possible; if so: I, Schutz grants anyone the right to use this work for any purpose, without any conditions, unless such conditions are required by law. |