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Data & Analytics · Intermediate

Poisson Distribution

The distribution of the count of events in a fixed interval of time or space, when events occur independently at a constant average rate λ.

Definition

In a Poisson distribution the mean equals the variance (λ). It models arrivals, calls per hour and defects per unit area.

Example

Calls to a help desk averaging 12 per hour.

Exam tip

Counts per interval = Poisson; time between events = exponential.

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