Beskrivelse

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 ${\displaystyle x}$ variable	9.0
Variance of each ${\displaystyle x}$ variable	11.0
Mean of each ${\displaystyle y}$ variable	7.5
Variance of each ${\displaystyle y}$ variable	4.12
Correlation between each ${\displaystyle x}$ and ${\displaystyle y}$ variable	0.816
Regression line	${\displaystyle y=3+0.5x}$

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.

 

Vektorgrafikken blev lavet med R.

Licensering

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.

Dette værk er fri software; du kan videredistribuere det og/eller ændre det under betingelserne i GNU General Public License som er udgivet af Free Software Foundation; enten version 2 af licensen, eller enhver senere version. Dette arbejde er distribueret i håb om at det vil være nyttigt, men uden nogen form for garanti, uden selv de underforståede garantier salgbarhed eller egnethed til et bestemt formål. Se version 2 og version 3 af licensen GNU General Public License for flere detaljer.http://www.gnu.org/licenses/gpl.htmlGPLGNU General Public Licensetruetrue

Derivative works

Derivative works of this file:

• Anscombe's quartet.svg
• Anscombe's quartet 2.svg