PD of DRV lists all the possible values that the random variable can assume and their corresponding probabilities.

The mean of a discrete random variable 𝑥 is also called its expected value and is denoted by 𝐸(𝑥)

𝝁 = 𝜮𝒙𝑷(𝒙)
𝑬(𝒙) = 𝜮𝒙𝑷(𝒙)

𝝈 = √𝚺𝒙^𝟐𝑷(𝒙) – 𝝁^2