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Which of the following statements are correct ?

(A) var(aX+b)=a2var(X)\text{var}(aX + b) = a^2 \text{var}(X)

(B) var(X)=E(X2)−{E(X)}2\text{var}(X) = E(X^2) - \{E(X)\}^2

(C) E(aX+b)=aE(X)+bE(aX + b) = aE(X) + b

(D) E(X)=∑i=1npixi2E(X) = \sum_{i=1}^{n} p_i x_i^2

Choose the correct answer from the options given below :

Solution

✅ Correct Option: 3

(A) var(aX+b)=a2var(X)\text{var}(aX + b) = a^2 \text{var}(X) - True.

(B) var(X)=E(X2)−{E(X)}2\text{var}(X) = E(X^2) - \{E(X)\}^2 - True.

(C) E(aX+b)=aE(X)+bE(aX + b) = aE(X) + b - True.

(D) E(X)=∑pixiE(X) = \sum p_i x_i, not ∑pixi2\sum p_i x_i^2 - False.

Hence (A), (B), (C) only.

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