AI engineering glossary · Probability
What is conditional probability?
Conditional probability: The probability that one event happens given that another event is known to have happened, written P(A | B) = P(A and B) / P(B). It restricts attention to the cases where the condition holds and is the foundation of learning from evidence.
Conditional probability: an example
If 5% of emails are spam and contain 'lottery', while 6% contain 'lottery', P(spam | lottery) = 0.05 / 0.06, about 0.83.
Related terms
More Probability terms
- Confounding variable
- Continuous random variable
- Correlation coefficient
- Correlation vs causation
- Covariance
- Cumulative distribution function
- Dependent events
- Discrete random variable
Where you learn it
Conditional probability is part of the AI Engineering Program, which teaches it with notes, a hands-on lab and an exam. The first lesson is free.