中等MATH-PROB-010
A and B are mutually exclusive, and both have positive probability. They
A. cannot be independent✓ 答案
B. must be independent
C. must have equal probability
D. satisfy P(A | B) = 1
解說
If both probabilities are positive, P(A)P(B) > 0, but mutual exclusion forces P(A ∩ B) = 0. The product rule for independence therefore fails.