Medical case histories indicate that different illnesses may produce iden- tical symptoms. Suppose that a particular set of symptoms, denoted H, occurs only when any one of three illnesses, Il, 12, or I3, occurs. Assume that the simultaneous occurrence of more that one of these illnesses is impossible and that Pal) = 0.01, 13(12) = 0.005, P03) = 0.02. The probabilities of developing the set of symptoms H, given each of these illnesses, are known to be P(H | 11) = 0.90,P(H | 12) = 0.95, P(H | 13) = 0.75. Assuming that an ill person exhibits the symptoms, H, what is the probability that the person has illness 11