444 CHAPTER 8 Hypothesis Testing with Two Samples 14. Therapeutic Taping A physical therapist claims that the use of a specific type of therapeutic tape reduces pain in patients with chronic tennis elbow. The table shows the pain levels on a scale of 0 to 10, where 0 is no pain and 10 is the worst pain possible, for 15 patients with chronic tennis elbow when holding a 1 kilogram weight. At a = 0.05, is there enough evidence to support the therapist’s claim? (Adapted from BioMed Central, Ltd.) Patient 1 2 3 4 5 6 7 8 Pain level (before taping) 7 7 4 4 8 5 3 9 Pain level (after taping) 6 5 1 1 4 0 0 5 Patient 9 101112131415 Pain level (before taping) 3 1 1 3 5 4 2 Pain level (after taping) 0 0 3 2 3 1 3 15. Gasoline Prices A reporter claims that U.S. gasoline prices increased from May to June of 2021. The table shows the prices (in dollars per gallon) of unleaded gasoline at 12 randomly selected U.S. gasoline stations during May and June of 2021. At a = 0.005, is there enough evidence to support the reporter’s claim? (Adapted from U.S. Energy Information Administration) Station 1 2 3 4 5 6 Price (May) 3.19 2.92 2.95 3.02 2.90 2.90 Price (June) 3.19 2.97 2.99 3.09 2.88 2.95 Station 7 8 9 10 11 12 Price (May) 2.91 2.91 3.01 3.05 2.92 2.93 Price (June) 2.90 2.96 3.05 3.09 2.91 2.98 16. Entry Level Salaries A career counselor claims that entry level receptionists earn more than entry level customer support representatives in Dallas, Texas. The table shows the salaries (in dollars) paid to entry level customer support representatives and receptionists at seven randomly selected companies in Dallas. At a = 0.005, is there enough evidence to support the career counselor’s claim? (Adapted from Salary.com) Company 1 2 3 4 5 6 7 Customer support salary 26,000 28,750 26,260 30,130 32,200 23,200 26,675 Receptionist salary 31,550 30,740 30,380 28,040 28,550 29,960 28,420
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