Poisson Approximation to the Binomial



when the value of n in a binomial distribution is large and the value of p is very small, the binomial distribution can be approximated by a poisson distribution.

if n > 20 and np < 5 or nq < 5 then the poisson is a good approximation.

Key Skills

solve problems involving binomial probability by approximating to the poisson distribution.


poisson distributionbinomial distributionparametermean,standard deviation.