Question

How do you know when to use a Poisson distribution or binomial distribution ?

Answer 1

Use of poisson distribution or binomial distribution:

Binomial Distribution:

This method is used when an exact probability of an event is given. It describes the distribution of binary data from a finite sample. Therefore, it gives the probability of getting $r$ events out of $n$ trials.

Poisson Distribution:

It is used when mean probability of an event occurring per unit time is given. It describes the distribution of binary data from an infinite sample. Therefore, it gives the probability of getting $r$ events in a population.