Poisson Distribution

Poisson distribution is a limiting process of binomial distribution. Poisson distribution occurs when there are events which do not occur as outcomes of a definite number of outcomes.

Poisson distribution is used under the following conditions:

Number of trials n tends to infinity

Probability of success p tends to zero and

np = l is finite.

Importance of Poisson distribution:-

The poisson distribution can be used to explain the behaviour of the discrete random variable where the probability of success of the event is very small and the total number of possible cases sufficiently large. As such poisson distribution has found application in a variety of fields such as queuing theory insurance, Physics, Biology, Business, Economics and Industry.

Examples:-

• The number of telephone calls arriving at a telephone switch board in unit time.
• The number of customers arriving at the super market.
• The number of defects per unit of manufactured product.
• To count the number of bacteria per unit.
• The number of accidents taking place per day on a busy road.