Q. For a random variable $X,E(X) = 3\ and\ E\left( X^{2} \right) = 11.$ Then, variable of $X$ is
A) 8
B) 5
C) 2
D) 1
Explanation
(c)
Given that, $E(X) = 3\ and\ E\left( X^{2} \right) = 11$
Variance of $X = E\left( X^{2} \right) - \left\lbrack E(X) \right\rbrack^{2}$
$= 11 - (3)^{2} = 11 - 9 = 2$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.