Consider the following statements where X is a random variable and a, b are real numbers : (A) $E(aX+b)=aE(X)+b$ (B) $E(aX+b)=a^2E(X)+b$ (C) $Var(aX+b)=a^2Var(X)$ (D) $Var(aX+b)=aVar(X)+b$ (E) $Var(X)=[E(X)]^2+E(X^2)$ Choose the correct answer from the options given below : |
(A) and (B) Only (A) and (C) Only (B), (C), (D) Only (C), (E) Only |
(A) and (C) Only |
$\text{Evaluate each statement:}$ $(A)\;E(aX+b)=aE(X)+b\;\text{— True}.$ $(B)\;E(aX+b)=a^2E(X)+b\;\text{— False}.$ $(C)\;\text{Var}(aX+b)=a^2\text{Var}(X)\;\text{— True}.$ $(D)\;\text{Var}(aX+b)=a\text{Var}(X)+b\;\text{— False}.$ $(E)\;\text{Var}(X)=[E(X)]^2+E(X^2)\;\text{— False, since }\text{Var}(X)=E(X^2)-[E(X)]^2.$ $\text{Correct statements are (A) and (C).}$ |