+128406 Mean = [ 10 + 19 + 21 + 28 + 12 + 20 + 16 ] / 7 = 18
Squared differences from mean
(10 - 18)^2 = (-8)^2 = 64
(19 - 18)^2 = 1^2 = 1
(21 - 18)^2 = 3^2 = 9
(28 -- 18)^2 = 10^2 = 100
(12 - 18)^2 = (-6)^2 = 36
(20 - 18)^2 = 2^2 = 4
(16 - 18) ^2 = (--2)^2 = 4
Variance = sum of squared differences / number of values = [ 64 + 1 + 9 + 100 + 36 + 4 + 4 ] / 7 = 31.14
