Mean, Variance, and Standard Deviation

• Mean - the expected value is a "weighted average" of the values that the discrete random variable

  • μ = E(X) =  Σ [X ⋅ P(X)]
• Variance and Standard Deviation - describes the spreadness/dispersion of the data

  • σ² = Σ[X² ⋅ P(X)] - μ²
  • σ² = Var(X) = E(X²) - μ²