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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()
  

 

本vector image使用R創作。

此作品已由其作者，Schutz，釋出至公有領域。此授權條款在全世界均適用。 這可能在某些國家不合法，如果是的話： Schutz授予任何人有權利使用此作品於任何用途，除受法律約束外，不受任何限制。

 

本vector image使用R創作。