Which statement is true about the Addition Law?

The Addition Law of probability states that the probability of the union of two events A and B can be found by adding the individual probabilities of the events and subtracting the probability of their intersection. In statistical terms, this is expressed as P(A ∪ B) = P(A) + P(B) - P(A ∩ B).

This formulation accounts for the overlap that exists when both events A and B occur, which is captured in P(A ∩ B). If both probabilities were simply added without subtracting the intersection, it would result in counting the overlapping outcomes twice. By subtracting P(A ∩ B), we ensure that we are accurately calculating the total probability of either event occurring.

This principle is foundational in probability and crucial for understanding more complex scenarios involving multiple events. Recognizing that the intersection needs to be subtracted is essential for correctly applying the Addition Law. Therefore, the correct statement reflects this essential relationship and the proper methodology for calculating probabilities in combined events.