Poisson distribution
Noun
Meaning
a theoretical distribution that is a good approximation to the binomial distribution when the probability is small and the number of trials is large
Source: WordNetSynonyms
Hypernyms
Examples
For example, one talks about "a Poisson distribution with mean value λ".
For occurrences of “contagious” discrete events, like tornado outbreaks, the Polya distributions can be used to give more accurate models than the Poisson distribution by allowing the mean and variance to be different, unlike the Poisson.
Hence a Poisson distribution is not an appropriate model.
His significant publications include: * In 1909 - "The Theory of Probabilities and Telephone Conversations" - which proves that the Poisson distribution applies to random telephone traffic.
If the null hypothesis predicts (say) on average 9 counts per minute, then according to the Poisson distribution typical for radioactive decay there is about 41% chance of recording 10 or more counts.
In such cases, the observations are overdispersed with respect to a Poisson distribution, for which the mean is equal to the variance.