10 Questions
| Total Attempts: 590

. V

Questions and Answers

- 1.Records from a random sample of dairy farms for the years 1998-2003 yielded the information below on the number of male and female calves born at various times of the day. What is the probability that a randomly selected calf was born in the night or was a female? Day Evening Night TOTAL Males 129 15 117 261 Females 118 18 116 252 TOTAL 247 33 233 513
- A.
369/513

- B.
485/513

- C.
116/513

- D.
116/252

- E.
116/233

- 2.A fast-food restaurant has many products for sale. Suppose that 60% of all customers order a hamburger of some kind, 12% purchase a milkshake, and 5% order both. If a customer is randomly selected, what is the probability that he or she ordered neither a hamburger nor a milkshake?
- A.
0.05

- B.
0.28

- C.
0.33

- D.
0.48

- E.
0.60

- 3.If P(A) = 0.25 and P(B) = 0.34, what is P(A U B) if A and B are independent?
- A.
0.085

- B.
0.505

- C.
0.590

- D.
0.675

- E.
There is insufficient information to answer this question.

- 4.Suppose that for a certain coastal city, in any given year the probability of a major hurricane hitting is 0.4, the probability of flooding is 0.3, and the probability of both a major hurricane and flooding is 0.2. What is the probability of flooding given that a major hurricane hits?
- A.
0.200

- B.
0.286

- C.
0.500

- D.
0.667

- E.
0.750

- 5.A large bakery has many products for sale. Suppose that 70% of all customers of the bakery order donuts, 50% order cinnamon rolls, and 40% order both. If a customer is randomly selected, what is the probability that they ordered either donuts or cinnamon rolls but not both?
- A.
20%

- B.
24%

- C.
40%

- D.
48%

- E.
60%

- 6.The following data were gathered from a large random sample as part of a study to compare yearly income with highest attained education level. Among those who earned over $60,000, what is the probability that the person has earned a bachelor's degree? $60,000 or less Over $60,000 TOTAL Graduate Degree 77 63 140 Bachelor's Degree 91 59 150 High School Grad 101 29 130 Did Not Graduate HS 42 15 57 TOTAL 311 166 477
- A.
0.124

- B.
0.348

- C.
0.355

- D.
0.393

- E.
0.607

- 7.A large sales company recruits many graduating students from universities in its workforce. Thirty percent of those hired for management positions come from private universities and colleges and rest from public colleges and universities. It is very expensive and time-consuming to train new managers, so the company is examining its retention rate (those still working for the company after six years) of these hires. Over the past six years, 35% of these managers who were hired from private schools had left for other jobs, while 20% of those from public schools had done so. What is the probability that a randomly selected person, who left the company within the past six years, was hired from a private university or college?
- A.
0.1050

- B.
0.4286

- C.
0.2308

- D.
0.3500

- E.
0.2450

- 8.Given that 49 percent of the US Population are male, and 12.1 percent of the population are over 65 years in age, can we conclude that (.490)(.121) = 5.93 percent of the population are men older than 65?
- A.
Yes, by the multiplication rule

- B.
Yes, by conditional probabilities

- C.
Yes, by the Law of Large Numbers

- D.
No, because the events are not independent

- E.
No, because the events are not mutually exclusive

- 9.Suppose two events,
*E*and*F*, have nonzero probabilities*p*and*q*, respectively. Which of the following is*impossible*?- A.
P + q > 1

- B.
P - q < 0

- C.
P/q > 1

- D.
E and F are neither independent nor mutually exclusive.

- E.
E and F are both independent and mutually exclusive.

- 10.A travel agent books passages on three different tours, with half her customers choosing Tour T1, one-third choosing T2, and the rest choosing T3. The agent has noted that three-quarters of those who take tour T1 return to book passage again, two-thirds of those who take T2 return, and one-half of those who take T3 return. If a customer does return, what is the probability that the person first went on T2?
- A.
1/3

- B.
2/3

- C.
2/9

- D.
16/49

- E.
49/72