Question

Question 14 ::
The random variables X and Y have variances 0.2 and 0.5 respectively. Let Z= 5X-2Y. The
variance or
5​

Answer 1

Given:

The random variables X and Y have variances 0.2 and 0.5 respectively.

Let Z = 5X - 2Y.

To find:

The variance of Z is

Solution:

From given data, we have,

Var(X) = 0.2, Var(Y) = 0.5

We have,

Z = 5X - 2Y

So, we get,

Var(Z) = Var(5X - 2Y)

= Var(5X) + Var(2Y)

= 25Var(X) + 4Var(Y)

∴ The variance of Z is Var(Z) = 7.

Answer 2

Answer:7

Explanation: