Definition of 'Joint Probability'
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:
Investopedia explains '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.