simpangan baku dari data 7,6,8,8,9,5,9,6,5 adalah...

Data diurutkan terlebih dahulu :
5,5,6,6,7,8,8,9,9

Xi = 5,5,6,6,7,8,8,9,9
Fi = 5 (2),6 (2),7 (1),8 (2),9 (2) =9
Xi.Fi = 10,12,7,16,18 =63
Rata" (Xs) = Jumlah Xi.Fi / Jumlah Fi
=63/9 =7
Xi-Xs = (5-7=-2),(5-7=-2),(6-7=-1),(6-7=-1),(7-7=0),(8-7=1),(8-7=1),(9-7=2),(9-7=2)
Xi-Xs^2=4,4,1,1,0,1,1,4,4
Fi.(Xi-Xs^2) = (2×4=8),(2×1=2),(1×0=0),(2×1=2),(2×2=4) =16

Jadi,Ragam = Jumlah Fi.(Xi-Xs^2) /Jumlah Fi
= 16 /9 =1,7

[tex]simpangan \: baku = \sqrt{1.7 \: } \: = 1.3[/tex]