Simpangan baku dari data 1,3,3,5,5,7,7,9 adalah

rata² = 1+3+3+5+5+7+7+9 / 8 = 48/8 = 5
S = akar (1-5)²+ (3-5)²+ (3-5)²+ (5-5)²+
(5-5)²+ (7-5)²+ (7-5)²+ (9-5)² / 8
= akar (-4)²+ (-2)²+ (-2)²+0²+0²+2²+ 2²+ 4² / 8
= akar 16+4+4+0+0+4+4+16 / 8
= akar 48 / 8
= akar 6