Of 20 rats in a cage, 12 are males and 9 are infected with a virus that causes hemorrhagic fever. Of the 12 male rats, 7 are infected with the virus. One rat is randomly selected from the cage. (a) If the selected rat is found to be infected, what is the probability that it is a female? (b) If the selected rat is found to be a male, what is the probability that it is infected? (c) Are the events "the selected rat is infected" and "the selected rat is male" independent? Why or why not?