See the DrugPatentWatch profile for Compound
What does “compound probability” mean?
“Compound probability” usually refers to the probability of two or more events happening together (or one after another), using probability rules for combined events—such as intersection (both happen) or conditional probability (one affects the other).
How do you calculate the probability of two events happening together?
For two events A and B, the probability that both occur is the intersection:
- If you know they’re independent (A does not affect B):
P(A and B) = P(A) × P(B)
- If they’re not independent:
P(A and B) = P(A) × P(B | A)
Here, P(B | A) means “probability of B given that A already happened.”
What if the question is about “either/or” (union) instead?
If you want the probability that at least one of the events happens (A or B or both):
- P(A or B) = P(A) + P(B) − P(A and B)
The subtraction avoids double-counting cases where both happen.
What if the compound probability involves more than two events?
For three events A, B, and C:
- P(A and B and C) = P(A) × P(B | A) × P(C | A and B)
This generalizes the same “multiply with conditional probabilities” idea.
Are there common special cases you might need?
- Mutually exclusive events (cannot both happen): P(A and B) = 0, so P(A or B) = P(A) + P(B).
- Complement rule (useful for “not A”): P(not A) = 1 − P(A).
Quick check: what exact problem are you working on?
To calculate the specific compound probability you need, I’d need the event definitions and any given probabilities (and whether events are independent). If you paste the full question or the numbers, I can compute it.