WOLFRAM|DEMONSTRATIONS PROJECT

Normal Approximation to a Poisson Random Variable

​
parameter λ
20
zoom
If
λ
is a positive integer, then a Poisson random variable with parameter
λ
can be thought of as a sum of
λ
independent Poisson random variables, each with parameter one. It is a consequence of the central limit theorem that for large values of
λ
such a random variable can be well approximated by a normal random variable with the same mean and variance.