For a Discrete Random Variable X, Which of the Following $\sum f\left(x_{i}\right)$

Multiple Choice

For a discrete random variable X, which of the following computes the expected value?

A) $\sum f\left(x_{i}\right)$

B) $\sum_{i=1}^{\infty} x_{i} f\left(x_{i}\right)$

C) $\sum_{i=1}^{\infty} x_{i}$

D) $\sum \frac { f ( x ) } { x }$