Question

Assuming the variance of four numbers w, x, y, and z as 9. Find the variance of 5w, 5x, 5y and 5z.

(a) 225

(b) 5/9

(c) 9/5

(d) 54

The question was posed to me during an interview.

Enquiry is from Statistics topic in division Statistics of Mathematics – Class 11

Answer 1

Correct option is (a) 225

Explanation: (σx)^2 = h^2(σu)^2, if u = (x – h)/a

Now, h = (1/5). ⇒ Variance, (σu)^2 = 9 × 25 = 225