#1 In a recent year, about 37% of all infants born in a country were conceived through in-vitro fertilization (IVF). Of the IVF deliveries, about twenty-five percent resulted in multiple births.

(a) Find the probability that a randomly selected infant was conceived through IVF and was part of a multiple birth.

(b) Find the probability that a randomly selected infant conceived through IVF was not part of a multiple birth.

(c) Would it be unusual for a randomly selected infant to have been conceived through IVF and to have been part of a multiple birth? Explain.

#2 The accompanying table shows the results of a survey in which 250 male and 250

female workers ages 25 to 64 were asked if they contribute to a retirement savings plan at work. Complete parts (a) and (b) below.

	Contribute	Do not contribute	Total
Male	130	120	250
Female	140	110	250
Total	270	230	500

(a) Find the probability that a randomly selected worker contributes to a retirement savings plan at work, given that the worker is male.

(b) Find the probability that a randomly selected worker is female, given that the worker contributes to a retirement savings plan at work.

#3 Two cards are selected from a standard deck of 52 playing cards. The first card is not replaced before the second card is selected.

Find the probability of selecting a five and then selecting an eight.

#4 In a sample of 800 U.S. adults, 191 think that most celebrities are good role models. Two

U.S. adults are selected from this sample without replacement. Complete parts (a) through (c).

(a) Find the probability that both adults think most celebrities are good role models.

(b) Find the probability that neither adult thinks most celebrities are good role models.

(c) Find the probability that at least one of the two adults thinks most celebrities are good role models.

#5 The probability that a person in the United States has type B+ blood is 12%. Five

unrelated people in the United States are selected at random. Complete parts (a) through (d).

(a) Find the probability that all five have type B+ blood.

(b) Find the probability that none of the five have type B+ blood.

(c) Find the probability that at least one of the five has type B+ blood.

(d) Which of the events can be considered unusual? Explain.

#6 The accompanying table shows the numbers of male and female students in a particular country who received bachelor's degrees in business in a recent year. Complete parts (a) and (b) below.

	Business degrees	Nonbusiness degrees	Total
Male	190,354	618,491	808,845
Female	162,387	943,643	1,106,030
Total	352,741	1,562,134	1,914,875

(a) Find the probability that a randomly selected student is male, given that the student received a business degree.

(b) Find the probability that a randomly selected student received a business degree, given that the student is female.