x̅ = Σxᵢ
n
= 2 + 4 + 5 + 7 + 7 + 8 + 9
7
= 42
7
= 6
Variansi:
V = S² = 1 Σⁿ ( xᵢ – x̅)²
n i=1
= ⅐((2-6)² + (4-6)² + (5-6)² + 2(7-6)² +
(8-6)² + (9-6)²)
= ⅐((-4)² + (-2)² + (-1)² + 2 × 1² + 2² + 3²)
= ⅐(16 + 4 + 1 + 2 + 4 + 9)
= ⅐ × 36 = 5,14
Kaprikornus, variansi data yakni 5,14.