Poisson probability
Poisson probability: use expected count λ, observed count k. Review the formula, worked example and calculation steps.
Inputs
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Formula & explanation
P(X=k) = exp(−λ) λᵏ/k!
Variables & units
- Expected count λ
- Numeric value · minimum 0, maximum 1000
- Observed count k
- Numeric value · minimum 0, maximum 1000
Worked example
λ=3 and k=2 gives approximately 0.224042.
Assumptions
Counts independent events with constant expected intensity over the interval.
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Practice with an example
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