📘 Key Concept
Binomial probability: P(X=k) = C(n,k)·pᵏ·(1−p)ⁿ⁻ᵏ. Normal distribution: 68-95-99.7 rule. Standard deviation and variance measure spread.
Binomial: P(X=k) = C(n,k)·pᵏ·(1−p)ⁿ⁻ᵏ
Permutation: P(n,r) = n!/(n−r)!
Combination: C(n,r) = n!/[r!(n−r)!]