Variability sample question

Question

Calculate SS(sum of squares), variance, and standard deviation for the following Sample of scores: 3,12,5,11,7.

Answer 1

3+12+5+11+7= 38

n=5

mean= 38/5

38/5 - 15/5 = 13/5 13/5^2 = 169/25

38/5 -60/5 =-22/5 -22/5^2 = 484/25

38/5-25/5 = 13/5 13/5^2=169/25

38/5-55/5= -17/5 -17/5^2 = 289/25

38/5-35/5=3/5 3/5^2 = 9/25

n=5

n-1=4

SS= (169+484+169+289+9)/25 = 1120/25

variance = 1120/25/(n-1) = 1120/25/4=1120/100

standard deviation = sqr(1120/25/4) = (1/10)sqr1120= (1/5)sqr280 = (2/5)sqr70 = about (2/5)(8.37)=3.35