Poisson Distribution

Poisson Distribution Tutorial


In statistics, poisson distribution is one of the discrete probability distribution. This distribution is used for calculating the possibilities for an event with the given average rate of value(λ). A poisson random variable(x) refers to the number of success in a poisson experiment.


f(x) = eλx / x!

λ is an average rate of value. x is a poisson random variable. e is the base of logarithm(e=2.718).


Consider, in an office 2 customers arrived today. Calculate the possibilities for exactly 3 customers to be arrived on tomorrow.

Step 1:

Find e. where, λ=2 and e=2.718 e = (2.718)-2 = 0.135.

Step 2:

Find λx. where, λ=2 and x=3. λx = 23 = 8.

Step 3:

Find f(x). f(x) = eλx / x! f(3) = (0.135)(8) / 3! = 0.18. Hence there are 18% possibilities for 3 customers to be arrived on tomorrow.

This tutorial will guide you to calculate the poisson distribution.

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