# Poisson distribution

noun
Pois·​son distribution | \ pwä-ˈsōⁿ- \

## Definition of Poisson distribution

: a probability density function that is often used as a mathematical model of the number of outcomes obtained in a suitable interval of time and space, that has its mean equal to its variance, that is used as an approximation to the binomial distribution, and that has the form {latex}f(x) = \frac{e^{-\mu}\mu^{x}}{{x!}}{/latex} where μ is the mean and x takes on nonnegative integral values

## First Known Use of Poisson distribution

1922, in the meaning defined above

## History and Etymology for Poisson distribution

Siméon D. Poisson †1840 French mathematician

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## The first known use of Poisson distribution was in 1922

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