Let X be a discrete random variable. Then the variance of X is: - Vidyadip

MCQ

Let $X$ be a discrete random variable. Then the variance of $X$ is:

A
$E(X^2)$
B
$E(X^2) + (E(X))^2$
✓
$E(X^2) - (E(X))^2$
D
$\sqrt{\text{E}(\text{X}^2)-(\text{E}(\text{X}))^2}$

✓

Answer

Correct option: C.

$E(X^2) - (E(X))^2$

Since, the variance of a discrete random variable $X$ is given by :
Var $(X) = E(X^2) - (E(X))^2$
Hence, the correct alternative is option $(c).$

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