Poisson distribution

Typical Poisson distribution

The Poisson distribution is a probability distribution. It is named after Siméon Denis Poisson who discovered it in 1838. It measures the probability that a certain number of events occur within a certain period of time. The events need to be unrelated to each other. They also need to occur with a known average rate.

Examples of this distribution are:

• The numbers of cars that pass on a certain road in a certain time.
• The number of telephone calls a call center receives per minute.
• The number of light bulbs that burn out (fail) in a certain amount of time.
• The number of mutations in a given stretch of DNA after a certain amount of radiation.
• The number of errors that occur in a system.