Question

The variance of random variable $X$ i.e. ${\sigma }_x^2$ or var$(X)$ is equal to

• A. $E\left(X^2\right)+{\left[E\left(X^2\right)\right]}^2$
• B. $E(X)-[E(X^2)]$
• C. $E(X^2)-[E(X){]}^2$
• D. None of these

Answer 1

Answer: (C)

Correct answer is (c) $E(X^2)-[E(X){]}^2$