3 Review Exercises 180 CHAPTER 3 Probability Section 3.1 In Exercises 1–4, identify the sample space of the probability experiment and determine the number of outcomes in the event. Draw a tree diagram when appropriate. 1. Experiment: Tossing four coins Event: Getting three heads 2. Experiment: Rolling 2 six-sided dice Event: Getting a sum of 4 or 5 3. Experiment: Choosing a month of the year Event: Choosing a month that begins with the letter J 4. Experiment: Guessing the gender(s) of the three children in a family Event: Guessing that the family has two boys In Exercises 5 and 6, use the Fundamental Counting Principle. 5. A student must choose from seven classes to take at 8:00 a.m., four classes to take at 9:00 a.m., and three classes to take at 10:00 a.m. How many ways can the student arrange the schedule? 6. The state of Virginia’s license plates have three letters and four digits. Assuming that any letter or digit can be used, how many different license plates are possible? In Exercises 7–12, classify the statement as an example of classical probability, empirical probability, or subjective probability. Explain your reasoning. 7. On the basis of prior counts, a quality control officer says there is a 0.05 probability that a randomly chosen part is defective. 8. The probability of randomly selecting five cards of the same suit from a standard deck of 52 playing cards is about 0.002. 9. The chance that Corporation A’s stock price will fall today is 75%. 10. The probability that a person can roll his or her tongue is 70%. 11. The probability of rolling 2 six-sided dice and getting a sum of 9 is 1 9. 12. The chance that a randomly selected person in the United States is between 12 and 18 years old is about 8.9%. (Source: U.S. Census Bureau) In Exercises 13 and 14, use the table, which shows the approximate distribution of the sizes of firms for a recent year. (Adapted from North American Industry Classification System) Number of employees 1 to 4 5 to 9 10 to 19 20 to 99 100 or more Percent of firms 78.5% 11.5% 4.9% 4.0% 1.1% 13. Find the probability that a randomly selected firm will have more than four employees. 14. Find the probability that a randomly selected firm will have fewer than 10 employees.
RkJQdWJsaXNoZXIy NjM5ODQ=