Probability

Poisson Distribution

Compute P(X=k) = λáµe⁻λ/k! for rare events with rate λ. Includes CDF, mean = λ, variance = λ, and PMF chart.

Live Calculator · Step-by-Step · Probability

Inputs

λ — rate (λ > 0)

k — target count (k ≥ 0)

Result

Enter values and calculate.

P(X = k)

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P(X ≤ k)

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P(X ≥ k)

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Mean μ = λ

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Variance σ² = λ

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SD σ = √λ

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Step-by-Step Work

Your explanation will appear here.

Poisson PMF — P(X = k)

Put It Into Practice

The calculator shows the steps — a quiz proves you can do them on your own.

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