AI engineering glossary · Probability
What is addition rule?
Addition rule (also called Inclusion-exclusion for two events): For any two events, the probability that at least one occurs is the sum of their probabilities minus the probability that both occur: P(A or B) = P(A) + P(B) - P(A and B). The subtraction avoids counting the overlap twice.
Addition rule: an example
If 40% of users use Android, 30% use a tablet and 10% use both, P(Android or tablet) = 0.4 + 0.3 - 0.1 = 0.6.
Related terms
More Probability terms
- At-least-one probability
- Base rate
- Base rate fallacy
- Bayes' theorem
- Bayesian probability
- Bernoulli distribution
- Binomial distribution
- Birthday problem
Where you learn it
Addition rule is part of the AI Engineering Program, which teaches it with notes, a hands-on lab and an exam. The first lesson is free.