1. Poisson Distribution

2. Consider the following:
X= no. of flaws in a length of material
X= no. of lightening strikes in a particular area within a specified time.

3. We use the Poisson because:
Events occur independently of each other.
Events occur singly.
Events occur at a constant rate over a time interval.
Events tend to be random or rare.
Mean should be around the same as the poisson.

4. How do we calculate Poisson probabilities?
The Poisson dist is applied using a parameter,λ, lambda. This is the mean number of occurrences of an event over a time interval.
X~Po(λ)

5. Examples
Using X~Po(λ=3), find
P(X=0)
P(X=4)
P(X≤4)
P(X>7)

7. Ex 1A page 7