2. the average annual income of an american citizen is normally distrib with a mean of $40,000 and a standard deviation of $13000. a. what is the probability that a randomly selected person will hav income of no more than $ 60,000? b. what is the probability that a randomly selected person will hav income of at least $65,000? c. what percentage of person will have an income of $20,000 to $65,000 d. what is the probability that a randomly selected person will have income at most $70000?