If p ( A or B ) = p ( A ) + p ( B ) then A and B must be _________.
A) dependent
B) mutually exclusive
C) overlapping
D) continuous

Question

Quizplus · Accepted Answer

If A and B are independent events, then the probability of the intersection of the events is equal to the product of their individual probabilities. Thus, p(A and B) = p(A) x p(B), which is not equal to p(A) + p(B) unless one of the probabilities is equal to zero. Therefore, A and B must be mutually exclusive events where they cannot occur at the same time. For mutually exclusive events A and B, p(A or B) = p(A) + p(B).

If P ( a or B ) = P