Poisson Distribution
To view the Poisson tables click here.
Conditions
- 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
Questions
- XB() Find P(X=15)
- XB() Find P(X=0)
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Answers
- ANS
- ANS - This can be found by looking in the tables for P(X≤0)
- ANS
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