Variabel acak diskrit X — distribusi probabilitas

Σ P(x) (cek)
1,000
Mean μ = E(X)
Variansi σ²
SD σ

E(X) = Σ x·P(x)  |  Var(X) = Σ (x−μ)²·P(x) = E(X²) − [E(X)]²