9-3 Matched Pairs 477 In Exercises 5–16, use the listed paired sample data, and assume that the samples are simple random samples and that the differences have a distribution that is approximately normal. 5. Measured and Reported Weights Listed below are measured and reported weights (lb) of random female subjects (from Data Set 4 “Measured and Reported” in Appendix B). a. Use a 0.05 significance level to test the claim that for females, the measured weights tend to be higher than the reported weights. b. Construct the confidence interval that could be used for the hypothesis test described in part (a). What feature of the confidence interval leads to the same conclusion reached in part (a)? Measured 147.3 268.7 213.4 201.3 107.1 172.0 187.4 132.5 122.1 151.9 Reported 142 267 210 204 107 176 187 135 122 150 6. Do Men Talk Less than Women? Listed below are word counts of males and females in couple relationships (from Data Set 14 “Word Counts” in Appendix B). a. Use a 0.05 significance level to test the claim that men talk less than women. b. Construct the confidence interval that could be used for the hypothesis test described in part (a). What feature of the confidence interval leads to the same conclusion reached in part (a)? Men 13,560 18,876 13,825 9274 20,547 17,190 Women 21,261 12,964 33,789 8709 10,508 11,909 7. The Freshman 15 The “Freshman 15” refers to the belief that college students gain 15 lb (or 6.8 kg) during their freshman year. Listed below are weights (kg) of randomly selected male college freshmen (from Data Set 13 “Freshman 15” in Appendix B). The weights were measured in September and later in April. a. Use a 0.01 significance level to test the claim that for the population of freshman male college students, the weights in September are less than the weights in the following April. b. Construct the confidence interval that could be used for the hypothesis test described in part (a). What feature of the confidence interval leads to the same conclusion reached in part (a)? c. What do you conclude about the Freshman 15 belief? September 67 68 87 81 60 70 68 68 80 April 67 68 88 82 61 71 69 69 82 8. QWERTY vs Dvorak Currently, keyboards have the keys configured in an arrangement referred to as “QWERTY” because of the placement of those particular letters on the second row from the top. Supposedly, that configuration was designed to slightly slow typing so that keys would not jam in typewriters commonly used in days of yore. The Dvorak keyboard configuration is claimed to be more efficient by arranging keys according to frequency of use. Listed below are difficulty ratings of typing different words on each of the two keyboards (based on data collected by the author). The data are paired according to the same word used on both keyboards, and higher numbers correspond to words that are more difficult to type. a. Use a 0.01 significance level to test the claim that word difficulty scores are higher with the QWERTY keyboard. b. Construct the confidence interval that could be used for the hypothesis test described in part (a). What feature of the confidence interval leads to the same conclusion reached in part (a)? QWERTY 56681072210582542 Dvorak 331354205140350
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