Question

Observations for a group, sum of square of observations form mean is 521 and variance is 52.1 then number of observations are _______

(a) 10

(b) 100

(c) 101

(d) 11

Answer 1

The correct option (a) 10

Explanation:

Variance = (S.D.)² = S² 

and     S² = [{∑(xi – x)²}/n]

given: S² = 52.1 and ∑(xi – x)² = 521

∴ n = [(521)/(52.1)] = 10

∴ Number of observations = 10.