402 CHAPTER 8 Hypothesis Testing 18. Mendelian Genetics When Mendel conducted his famous genetics experiments with peas, one sample of offspring consisted of 428 green peas and 152 yellow peas. Use a 0.01 significance level to test Mendel’s claim that under the same circumstances, 25% of offspring peas will be yellow. What can we conclude about Mendel’s claim? 19. Lie Detectors Trials in an experiment with a polygraph yield 98 results that include 24 cases of wrong results and 74 cases of correct results (based on data from experiments conducted by researchers Charles R. Honts of Boise State University and Gordon H. Barland of the Department of Defense Polygraph Institute). Use a 0.05 significance level to test the claim that such polygraph results are correct less than 80% of the time. Based on the results, should polygraph test results be prohibited as evidence in trials? 20. Tennis Instant Replay The Hawk-Eye electronic system is used in tennis for displaying an instant replay that shows whether a ball is in bounds or out of bounds so players can challenge calls made by referees. In a recent U.S. Open, singles players made 1569 challenges and 446 of them were successful, with the call overturned. Use a 0.01 significance level to test the claim that less than 30% of the challenges are successful. What do the results suggest about the ability of players to see calls better than referees? 21. Touch Therapy When she was 9 years of age, Emily Rosa did a science fair experiment in which she tested professional touch therapists to see if they could sense her energy field. She flipped a coin to select either her right hand or her left hand, and then she asked the therapists to identify the selected hand by placing their hand just under her hand without seeing it and without touching it. Among 280 trials, the touch therapists were correct 123 times (based on data in “A Close Look at Therapeutic Touch,” Journal of the American Medical Association, Vol. 279, No. 13). Use a 0.10 significance level to test the claim that touch therapists use a method equivalent to random guesses. Do the results suggest that touch therapists are effective? 22. Online Friends A Pew Research Center poll of 1060 teens aged 13 to 17 showed that 57% of them have made new friends online. Use a 0.01 significance level to test the claim that half of all teens have made new friends online. 23. Road Rage In a survey of 2705 licensed drivers aged 16 and older, 33% of those respondents reported that they make angry gestures while driving (based on data from the Automobile Association of America). Use a 0.05 significance level to test the claim that among licensed drivers aged 16 and older, the percentage who make angry gestures while driving is equal to 35%. Does the conclusion change if the significance level is changed to 0.01? 24. Internet-Connected TV Penetration In a Leichtman Research Group survey of 1150 TV households, 74% of them had at least one Internet-connected TV device (e.g., Smart TV, standalone streaming device, connected video game console). A marketing executive wants to convey high penetration of Internet-connected TV devices, so he makes the claim that the percentage of all homes with at least one Internet-connected TV device is equal to 80%. Test that claim using a 0.05 significance level. 25. Super Bowl Wins Through the sample of the first 53 Super Bowls, 27 of them were won by teams in the National Football Conference (NFC). Use a 0.05 significance level to test the claim that NFC teams win the majority of Super Bowl games. 26. Supreme Court When Brett Kavanaugh was nominated to be a Supreme Court justice, a survey of 1144 Americans showed that 51% of them disapproved of Kavanaugh (based on a poll by the Washington Post and ABC News). USA Today published an article with this headline: “Majority of Americans Disapprove of Kavanaugh.” Use a 0.05 significance level to test the claim made in that headline. 27. Overtime Rule in Football Before the overtime rule in the National Football League was changed in 2011, among 460 overtime games, 252 were won by the team that won the coin toss at the beginning of overtime. Using a 0.05 significance level, test the claim that the coin toss is fair in the sense that neither team has an advantage by winning it. Did the coin toss appear to be fair prior to the overtime rule change?
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