simpang baku dari data 2,7,6,5,9,4,8,7 adalah

rata rata = 2+7+6+5+9+4+8+7/8 = 48/8 = 6
s^2 = (6-2)^2+(7-6)^2+(6-6)^2+(6-5)^2+(9-6)^2+(6-4)^2+(8-6)^2+(7-6)^2/6
=4^2+1^2+0^2+1^2+3^2+2^2+2^2+1^2/6
=16+1+0+1+9+4+4+1/6
=36/6 = 6
simpangan baku = akar 6