Given data set : 2 , 3, 3, 4, 4, 5 , 6 , 7 here no. of observation in data set = n= 8 S.No. 2 4 3 9 W 3 9 4 4 16 4 16 5 36 Oo 49 total Exi = 34 1= 164 mean = X = 34 - 4.25 8 Now Variance s 2 - 2 x2- Exil2 164 - 134 8 n - 1 8 - 1 = 164- 17 2 169 - 289 656- 289 7 4 = 7 28 = . 367 28 = 13. 1071 ~ 13-12 standard deviation : S = V32 = 3.6203 ~ 3-62 " coefficient of variation ( EV ) = S xloo = 3- 6203 X 140 X 4. 25 = 85 . 1835 - 85. 18.

My question is: How did 164-17/2 and 169-289 and so on?