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Original file (SVG file, nominally 945 × 630 pixels, file size: 57 KB)

Summary

This graphic represents the four datasets defined by Francis Anscombe for which some of the usual statistical properties (mean, variance, correlation and regression line) are the same, even though the datasets are different.

Property Value
Mean of each variable 9.0
Variance of each variable 11.0
Mean of each variable 7.5
Variance of each variable 4.12
Correlation between each and variable 0.816
Regression line

The graph was created by User:Schutz for Wikipedia on 13 June 2006 (and updated on 29 March 2010), using the R statistical project. The program that generated the graphic is given below; it is based on the example provided with the help page of the R dataset anscombe (accessible using the command data(anscombe); help and more information about the dataset is available using the command help(anscombe)), and was slightly modified to improve the result. The graph was directly exported in SVG format.

References:

  • Anscombe, Francis J. (1973) Graphs in statistical analysis. American Statistician, 27, 17–21.
  • R Development Core Team. R: A Language and Environment for Statistical Computing. R Foundation for Statistical Computing. Vienna, Austria. 2006. ISBN 3-900051-07-0. http://www.R-project.org
 svg("anscombe.svg", width=10.5, height=7)
 par(las=1)
 
 ##-- some "magic" to do the 4 regressions in a loop:
 ff <- y ~ x
 for(i in 1:4) {
   ff[2:3] <- lapply(paste(c("y","x"), i, sep=""), as.name)
   ## or   ff2 <- as.name(paste("y", i, sep=""))
   ##      ff3 <- as.name(paste("x", i, sep=""))
   assign(paste("lm.",i,sep=""), lmi <- lm(ff, data= anscombe))
 }
 
 ## Now, do what you should have done in the first place: PLOTS
 op <- par(mfrow=c(2,2), mar=1.5+c(4,3.5,0,1), oma=c(0,0,0,0),
           lab=c(6,6,7), cex.lab=1.5, cex.axis=1.3, mgp=c(3,1,0))
 for(i in 1:4) {
   ff[2:3] <- lapply(paste(c("y","x"), i, sep=""), as.name)
   plot(ff, data =anscombe, col="red", pch=21, bg = "orange", cex = 2.5,
        xlim=c(3,19), ylim=c(3,13),
        xlab=eval(substitute(expression(x[i]), list(i=i))),
        ylab=eval(substitute(expression(y[i]), list(i=i))))
   abline(get(paste("lm.",i,sep="")), col="blue")
 }
  
 dev.off()
 
The SVG code is valid.
 
This chart was created with R.

Licensing

The R project is licensed under the GPL [1]; since this image is a derived work of an example script provided with R, it is also licenced under the GPL.

However, all modifications made by User:Schutz are also licensed under the CC-BY-SA licence.

GNU head

This work is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or any later version. This work is distributed in the hope that it will be useful, but without any warranty; without even the implied warranty of merchantability or fitness for a particular purpose. See version 2 and version 3 of the GNU General Public License for more details.

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File history

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Date/TimeThumbnailDimensionsUserComment
current15:10, 29 March 2010Thumbnail for version as of 15:10, 29 March 2010945 × 630 (57 KB)Schutz
00:07, 15 January 2007Thumbnail for version as of 00:07, 15 January 2007990 × 677 (88 KB)Schutz
00:05, 15 January 2007Thumbnail for version as of 00:05, 15 January 2007990 × 677 (88 KB)Schutz
21:37, 13 June 2006Thumbnail for version as of 21:37, 13 June 20061,044 × 750 (94 KB)Schutz
18:27, 13 June 2006Thumbnail for version as of 18:27, 13 June 20061,125 × 875 (94 KB)Schutz

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