Poisson distribution
…PMF λ k e − λ k ! CDF Γ ( ⌊ k + 1 ⌋ , λ ) ⌊ k ⌋ ! , !}},} or e − λ ∑ j = 0 ⌊ k ⌋ λ j j ! , or Q ( ⌊ k + 1 ⌋ , λ ) (for k ≥ 0 , where Γ ( x , y ) is the upper incomplete gamma function, ⌊ k ⌋ is the floor function, and Q is the regularized gamma function) Mean λ Median ≈ ⌊ λ + 1 3 − 1 50 λ ⌋ Mode ⌈ λ ⌉ − 1 , ⌊ λ ⌋ Variance λ Skewness…