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Poisson Distribution
To view the Poisson tables click here.
  • Occur singly in time and space
  • The outcome is independent and random
  • Occurs at an average and constant rate
If a distribution satisfies the above conditions then it can be modelled as a Poisson Distribution. Hence X∼Po(λ) where lambda is the average rate.

Finding P(x=x)

Finding Other Probabilities

Finding E(X) and Var(X)

Approximating the Poisson Distribution
Normal Distribution
The Poisson distribution can be approximated to a normal distribution if λ is large (i.e. not in the tables). It is approximated as: 

Hypothesis Testing

  1. XB() Find P(X=15)
  2. XB() Find P(X=0)
  3. bg
  1. ANS
  2. ANS - This can be found by looking in the tables for P(X≤0)
  3. ANS