The Poisson cumulative distribution function is a discrete function defined for non-negative integers x. The Poisson distribution with mean μ > 0 is defined by the summation
Evaluate Numerically
PoissonDen
2;3
= .22404
PoissonDen
5;0.3
= 1.5002×10-5
PoissonDen
10;4
= 5.2925×10-3
The Poisson distribution can be used to approximate the binomial distribution when the probability is small and n is large; that is,