## What is a 'Joint Probability'

A joint probability is a statistical measure where the likelihood of two events occurring together and at the same point in time are calculated. Joint probability is the probability of event Y occurring at the same time event X occurs.

Notation for joint probability takes the form:

## BREAKING DOWN 'Joint Probability'

Joint probability is a measure of two events happening at the same time, and can only be applied to situations where more than one observation can be occurred at the same time.

For example, a joint probability can not be calculated when tossing a coin on the same flip. However, the joint probability can be calculated on the probability of rolling a 2 and a 5 using two different dice.