[R] Using R to illustrate the Central Limit Theorem

[Vincent Goulet]

Hi,

Not exactly what you asked for, but related.

I wrote the following little function to emulate a quincunx (a good 
illustration of the CLT, in my opinion):

quincunx <- function(nb.bins, nb.rows=nb.bins-1, nb.balls=2^nb.bins)
{
    x <- sample(c(0, 1), nb.balls * nb.rows, replace=TRUE)
    dim(x) <- c(nb.rows, nb.balls)
    hist(colSums(x), breaks=0:nb.rows, main="Number of balls per bin")
}

Idea: drop nb.balls in a quincunx with nb.bins bins at the bottom. The bin in 
which a ball ends up is the sum of nb.rows Bernouilli trials (where 0 stands 
for "left" and 1 for "right").

Hope this helps!

Le 21 Avril 2005 13:06, Paul Smith a écrit :
> Dear All
>
> I am totally new to R and I would like to know whether R is able and
> appropriate to illustrate to my students the Central Limit Theorem,
> using for instance 100 independent variables with uniform distribution
> and showing that their sum is a variable with an approximated normal
> distribution.
>
> Thanks in advance,
>
> Paul
>
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-- 
  Vincent Goulet, Professeur agrégé
  École d'actuariat
  Université Laval, Québec