Variability question

Question

Calculate SS (sum of squares), variance, and standard deviation for the following Sample of scores: 9,3,5,4,7,2,5.

Answer 1

n=7 scores

n-1=6

9+3+5+4+7+2+5=34=5

35/n = 35/7 = 5 mean

(5-9)^2 = 16

(5-3)^2 = 4

(5-4)^2 = 1

(5-7)^2 = 4

(5-2)^2 = 9

(5-5)^2 = 0

SS = 34

var = 34/6 = 17/3

standard deviation = sqr(17/3)