Poisson distribution

The poisson distribution is a class of discrete probability distributions.

It's well suited for modeling various physical phenomena.

A basic introduction to the concept

A basic intro aimed for the general public here.

Example

A certain event happens at unpredictable intervals. But for some reason, no matter how recent or long ago last time was, the probability that it will occur again within the next hour is exactly 10%.

Then the number of events per day is Poisson distributed.

Formal definition

Let X be a stochastic variable taking non-negative integer values with probability density function $P(X=k)=f(k)=e^{-\lambda }{\frac {\lambda ^{k}}{k!}}$. Then X follows the Poisson distribution with parameter $\lambda$.

See also

• Probability distribution
• Probability
• Probability theory

Related topics

• Exponential distribution

External links

• mathworld