AND Probability Calculator
Find the probability that two events both occur using the multiplication rule.
Formula
P(A ∩ B) = P(A) × P(B|A); if independent, P(B|A) = P(B)
Joint probability ≈ (50)×(50)÷100 · Joint probability as decimal ≈ (25)÷100
How to use
- Enter P(A) as a percentage.
- Enter P(B|A); for independent events, use P(B).
- Read the joint probability as a percentage and decimal.
Examples
- Two independent 50% events both occur with probability 25%.
Frequently asked questions
What does conditional mean?
P(B|A) is the chance of B once A is known to have occurred.
May I multiply the two marginal probabilities?
Only when the events are independent. For dependent events, enter the conditional probability.
What if P(A) is zero?
The intersection has probability zero; P(B|A) is then undefined, so the second value does not have a conditional interpretation.
Sources
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