Statistics & Probability

Poisson Probability

P(X = k) for rate λ.

Formula

Formula
P = λk e−λk!

Variables

SymbolDefinitionType & rangeUnitsRole
λ average rate computed result result
k occurrences integer (ℤ) input

Try it yourself

Interactive calculator
Result

Worked examples

Example 1
Givenλ = 3, k = 2
Result0.2240418077
Example 2
Givenλ = 5, k = 5
Result0.1754673698