Question

Suppose a population A has 100 observations 101, 102, ..., 200, and another population B has 100 observations 151, 152, ..., 250. If VA and VB represent the variances of the two populations, respectively then VA/ VB is

(a) 1

(b) 9/4

(c) 4/9

(d) 2/3.

Answer 1

(a) : Series A = 101, 102, 103, ......., 200 Series B = 151, 152, 153, ........., 250 Series B is obtained by adding a fixed quantity to each item of series A, we know that variance is independent of change of origin both series have the same variance so ratio of their variances is 1.