Question

7. Approximately 20% of U.S. workers are afraid that they will never be able to retire. Suppose 10 workers are randomly selected. What is the probability that none of the workers is afraid that they will never be able to retire? a. 0.095 b. 0.995 c. 0.1074 d. 0.1228

8. According to WSJ, about 30% of adults have 4 year college degrees. Out of five randomly selected adults, what’s the probability that three have college degrees? a. 0.13 b. 0.15 c. 0.17 d. 0.19

9. According to WSJ, about 30% of adults have 4 year college degrees. Out of five randomly selected adults, what’s the probability that four have college degrees? a. 0.028 b. 0.132 c. 0.360 d. 0.868

10. According to WSJ, about 30% of adults have 4 year college degrees. Out of five randomly selected adults, what’s the probability that five have college degrees? a. 0.001 b. 0.002 c. 0.003 d. 004

11. According to WSJ, about 30% of adults have 4 year college degrees. Out of five randomly selected adults, what’s the probability that AT LEAST 3 out of 5 have college degrees? a. 0.183 b. 0.174 c. 0.162 d. 0.158  

12. A bank manager estimates that an average of two customers enters the tellers' queue every five minutes. Assume that the number of customers that enters the tellers' queue is Poisson distributed. What is the probability that exactly seven customers enter the queue in a randomly selected 15-minute period? a. 0.0034 b. 0.1033 c. 0.1377 d. 0.1606

13. The foreclosure crisis has been particularly devastating in housing markets in much of the south and west United States, but even when analysis is restricted to relatively strong housing markets the numbers are staggering. For example, in 2017 an average of three residential properties were auctioned off each weekday in the city of Boston. What is the probability that exactly four foreclosure auctions occurred on a randomly selected weekday of 2017 in Boston? a. 0.1680 b. 0.1954 c. 0.2240 d. 0.8153

14. Particles (e.g. yeast cell) are suspended in a liquid medium at a concentration. A large volume of the suspension is thoroughly agitated, and then 1 ml is withdrawn. The concentration in this sample is 10 particles per ml. What is the probability that, in the entire liquid medium, the concentration is exactly 8 particles/ml? a. 0.0993 b. 0.1126 c. 0.8320 d. 0.0009

15. On average, 0.61 soldiers in each corp of the Prussian cavalry were kicked to death by horses each year. What is the probability that in the next year, exactly 3 soldiers will be kicked to death by a horse? a. 008 b. 0.01 c. 0.02 d. 0.03

16. Patients arrive at the emergency room of a hospital at the average rate of 6 per hour on weekend evenings. What is the probability of 4 arrivals in 30 minutes on a weekend evening? a. 0.152 b. 0.168 c. 0.174 d. 0.182

Answer 1