Expected Value of Discrete RV

Expectation Single RV Formula

$E(X)={\sum }_X^{}x{p}_x(x)$

• $X$ is the given random variable
• $x$ is the given trial
• $p_x(x)$ is the PMF

Alternate Formula

$E(X)={\sum }_{k=1}^{\infty }P(X>k)$