Statistics, R, Graphics and Fun » Bell-Shaped Curve http://yihui.name/en Yihui XIE Thu, 26 Aug 2010 03:32:16 +0000 en hourly 1 http://wordpress.org/?v=3.0.1 When “Bell-shaped” is Far Far Away from Gaussian http://yihui.name/en/2009/01/when-bell-shaped-is-far-far-away-from-gaussian/ http://yihui.name/en/2009/01/when-bell-shaped-is-far-far-away-from-gaussian/#comments Wed, 07 Jan 2009 13:38:17 +0000 Yihui Xie http://yihui.name/en/?p=58 I was surprised to find the density estimation of a constant was also “bell-shaped” by default when a friend passed some R code to me to illustrate CLT, but I realized the reason soon.

Downdload the R code here 
# png(width = 500, height = 300)
x = rep(0, 1000)
par(mfrow = c(1, 2), mar = c(4, 4, 0.1, 0.1))
plot(density(x), main = "")
plot(density(x), main = "")
rug(jitter(x))
# dev.off()

Note that I added a rug (jittered) to the right plot to tell you the true locations of the data points.

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