118 CHAPTER 3 Describing, Exploring, and Comparing Data different countries. What do the measures of variation tell us about the prices of a Big Mac in different countries? 5.3 5.3 2.6 3.2 3.4 2.3 6.8 5.1 4.8 4.4 2.8 1.9 In Exercises 21–24, find the coefficient of variation for each of the two samples; then compare the variation. (The same data were used in Section 3-1.) 21. Blood Pressure A sample of blood pressure measurements is taken from Data Set 1 “Body Data” in Appendix B, and those values (mm Hg) are listed below. The values are matched so that 10 subjects each have a systolic and diastolic measurement. Systolic: 118 128 158 96 156 122 116 136 126 120 Diastolic: 80 76 74 52 90 88 58 64 72 82 22. Parking Meter Theft Listed below are amounts (in millions of dollars) collected from parking meters by Brinks and others in New York City during similar time periods. A larger data set was used to convict five Brinks employees of grand larceny. The data were provided by the attorney for New York City, and they are listed on the Data and Story Library (DASL) website. A difference in variation suggests theft may have occurred. Do the two samples appear to have different amounts of variation? Collection Contractor Was Brinks 1.3 1.5 1.3 1.5 1.4 1.7 1.8 1.7 1.7 1.6 Collection Contractor Was Not Brinks 2.2 1.9 1.5 1.6 1.5 1.7 1.9 1.6 1.6 1.8 23. Pulse Rates Listed below are pulse rates (beats per minute) from samples of adult males and females (from Data Set 1 “Body Data” in Appendix B). Does there appear to be a difference? Male: 86 72 64 72 72 54 66 56 80 72 64 64 96 58 66 Female: 64 84 82 70 74 86 90 88 90 90 94 68 90 82 80 24. It’s a Small Wait After All Listed below are the fifty wait times (minutes) at 10 AM for the rides “It’s a Small World” and “Avatar Flight of Passage.” These data are found in Data Set 33 “Disney World Wait Times.” Do the two rides appear to have different amounts of variation? It’s a Small World 10 5 5 1010101015101010101010 5 101010 5 5 5 1010 5 10 5 1015 5 5 10 5 5 5 1510103010 5 101010 5 101510201515 Avatar Flight of Passage 180 195 110 150 180 150 150 180 150 150 165 150 120 165 135 150 75 90 85 105 75 135 120 150 105 135 105 105 150 90 70 120 90 120 135 210 135 150 225 150 165 150 135 150 180 120 150 180 225 165 Large Data Sets from Appendix B. In Exercises 25–28, refer to the indicated data set in Appendix B. Use software or a calculator to find the range, variance, and standard deviation. Express answers using appropriate units, such as “minutes.” 25. Body Temperatures Refer to Data Set 5 “Body Temperatures” in Appendix B and use the body temperatures for 12:00 AM on day 2. 26. Earthquakes Use the magnitudes (Richter scale) of the 600 earthquakes listed in Data Set 24 “Earthquakes” in Appendix B. In 1989, the San Francisco Bay Area was struck with an earthquake that measured 7.0 on the Richter scale. If we add that value of 7.0 to those listed in the data set, do the measures of variation change much? 27. Audiometry Use the hearing measurements from Data Set 7 “Audiometry.” Does it appear that the amounts of variation are different for the right threshold measurements and the left threshold measurements?
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