I. (ˈ)pwa]|sōⁿ-, -wä] noun
Usage: usually capitalized P
Etymology: after Siméon D. Poisson died 1840 French mathematician and statistician
: a distribution in statistics that is a good approximation to the binomial distribution when the probability of success in a single trial is very small and the number of trials is very large
II. pwäˈsōⁿ- noun
Usage: usually capitalized P
Etymology: after Siméon D. Poisson died 1840 French mathematician
: a probability density function that is often used as a mathematical model of the number of outcomes (as traffic accidents, atomic disintegrations, or organisms) obtained in a suitable interval of time and space, that has the mean equal to the variance, that is used as an approximation to the binomial distribution, and that has the form f(x) = e -μ μ x /x! where μ is the mean and x takes on nonnegative integral values