A statistical distribution that serves as a model for situations concerned with the number of successes per unit of observation, e.g. the number of phytoplankton caught per trawl. More strictly speaking, this is a limiting form of the binomial distribution when the probability of success for an individual trial approaches zero, the number of trials becomes infinite, and the product of these two quantities remains constant.
A statistical tool that assumes 3 conditions: for any one observation only two results are possible; the chances of these two results do not vary from one observation to the next; and successive observations are independent
discrete random variable X is said to follow a Poisson distribution with parameter m, written X ~ Po(m), if in a memoryless or completely random process, X represents a count of the number of random events that occur in a certain time interval or spatial area. For example, the number of cars passing a fixed point in a 5 minute interval; the number of calls received by a switchboard during a given period of time.