Poisson Probability Distribution

Poisson Random VariableProvides model for data that represent the

number of occurrences of a specified event in a given unit of time

X represents the number of events that occur in a period of time or space during which an average of such events can be expected to occur

Poisson Random Variable

!)(

k

ekxP

k

Standard Deviation

Poisson Approximation to the Binomial DistributionPoisson probability distribution provides an

accurate approximation to binomial probabilities

N must be largeµ=np is small, preferably np < 7