If two events A and B are such that Pr(A) is not zero and Pr(B) is not zero, what combinations of independent (I ), not independent (NI ), mutually exclusive (M), and not mutually exclusive (NM) are permissible? In other words, which of the four combinations (I, M), (NI, M), (I, NM), and (NI, NM) are permissible? Construct an example for those combinations that are permissible.