The Poisson distribution
(Siméon Denis Poisson,
1781-1840) can be obtained from the binomial distribution:
let the number of events N go to infinity, where the most probable number of successes
remains constant 1).
We can use the Poisson distribution in the case of a discrete probability process, with a constant frequency. Examples can be found in nuclear physics while counting elementary particles.
1) product of n and p, denoted as: a.