| Term: | Poisson distribution |
| Definition: |
A probability function that characterizes discrete random events occurring independently of one another within some definite time or space. It may be regarded as an approximation of the binomial distribution when the number of events becomes large and the probability of success becomes small. The Poisson distribution is expressed by: f(x) = (λxe-λ)/x!, where λ is the mean number of successes in the interval, e is the base of the natural logarithm, and x is the number of successes we are interested in. |