Message-ID: <201101161145.28281.Hugo.Mildenberger@web.de>
Date: 2011-01-16T10:45:27Z
From: Hugo Mildenberger
Subject: rootogram for normal distributions
Using R-2.12.1 and latticeExtra-0.6-14, I would like to understand
why a rootogram displaying samples from the Poisson distribution looks like I
expected it, whereas a rootogram using the normal distribution does not:
library(latticeExtra)
rootogram(~rpois(1000, lambda = 50), dfun = function(x) dpois(x, lambda = 50))
rootogram(~rnorm(1000), dfun = function(x) dnorm(x,mean(x),sd(x)))
I probably can't attach figures here. Thus a textual description of what I get may
suffice: With increasing sample size, the rootogram using random samples
from the Poisson distribution shows decreasing differences (bars are quickly
approaching the zero line), whereas the displayed differences for random
samples of the normal distribution are always large. The differences even increase
with sample size, i.e, the hanging bars tend to vanish for very large samples.