Discrete Probability Distributions

Probability Distribution

The probability distribution of a discrete random variable, X, is each possible value of the variable xi with a probability of pi.

0 ≤ pi ≤ 1

p1 + p2 + p3 + · · · + pn = Σpi = 1

The probability distribution is also called the probability function or the probability mass function.


Determine the probability distribution of all the possible outcomes that can be obtained by rolling a die.

x p i
1 p
2 p
3 p
4 p
5 p
6 p

Representation of the Probability Distribution

A discrete probability distribution is represented by a bar chart.

Discrete Probability Distribution