Question

If X is a random variable with E(X) = 6 and V(X) = 3, then E(X²) is equal to

• A. 33
• B. 36
• C. 39
• D. 42
• E. 27

Answer 1

The Correct Option is C

We are given the following information:

• \( E(X) = 6 \)
• \( V(X) = 3 \)

We can use the formula for variance:

\[ V(X) = E(X^2) - (E(X))^2 \]

Substitute the given values:

\[ 3 = E(X^2) - (6)^2 \] \[ 3 = E(X^2) - 36 \]

Now solve for \( E(X^2) \):

\[ E(X^2) = 3 + 36 = 39 \]

Answer: 39