If X is a random variable and a, b are real numbers, then which of the following statements are correct? (A) $\text{E[aX+b] = a E(X) + b}$ Choose the correct answer from the options given below: |
(A), (B) and (D) only (A) and (D) only (B) and (C) only (A), (C) and (D) only |
(A) and (D) only |
The correct answer is Option (2) → (A) and (D) only Given properties of random variable $X$ and real numbers $a, b$: (A) $E[aX+b] = a E(X) + b$ → True (linearity of expectation) (B) $\text{Var}(aX+b) = a^2 \text{Var}(X) + b$ → False, correct formula: $\text{Var}(aX+b) = a^2 \text{Var}(X)$ (C) $\text{Var}(aX+b) = a \text{Var}(X)$ → False, factor should be $a^2$ (D) $\text{Var}(X) = E(X^2) - [E(X)]^2$ → True (definition of variance) |