SECTION 8.3 Testing the Difference Between Means (Dependent Samples) 445 17. Product Ratings A company claims that its consumer product ratings (0–10) have changed from last year to this year. The table shows the company’s product ratings from the same eight consumers for last year and this year. At a = 0.05, is there enough evidence to support the company’s claim? Consumer 1 2 3 4 5 6 7 8 Rating (last year) 5 7 2 3 9 10 8 7 Rating (this year) 5 9 4 6 9 9 9 8 18. Passing Play Percentages The passing play percentages of 10 randomly selected NCAA Division 1A college football teams for home and away games in the 2020–2021 season are shown in the table. At a = 0.20, is there enough evidence to support the claim that passing play percentage is different for home and away games? (Source: TeamRankings) College 12345678910 Home passing play percentage 54.3 48.1 44.7 40.8 45.4 46.3 53.7 37.9 73.1 40.7 Away passing play percentage 52.9 59.3 47.6 43.2 46.8 42.6 49.9 44.6 49.6 40.2 19. Cholesterol Levels A food manufacturer claims that eating its new cereal as part of a daily diet lowers total blood cholesterol levels. The table shows the total blood cholesterol levels (in milligrams per deciliter of blood) of seven patients before eating the cereal and after one year of eating the cereal as part of their diets. At a = 0.05, is there enough evidence to support the food manufacturer’s claim? Patient 1 2 3 4 5 6 7 Total blood cholesterol level (before) 210 225 240 250 255 270 235 Total blood cholesterol level (after) 200 220 245 248 252 268 232 20. Obstacle Course On a television show, eight contestants try to lose the highest percentage of weight in order to win a cash prize. As part of the show, the contestants are timed as they run an obstacle course. The table shows the times (in seconds) of the contestants at the beginning of the season and at the end of the season. At a = 0.01, is there enough evidence to support the claim that the contestants’ times have changed? Contestant 1 2 3 4 5 6 7 8 Time (beginning) 130.2 104.8 100.1 136.4 125.9 122.6 150.4 158.2 Time (end) 121.5 100.7 90.2 135.0 112.1 120.5 139.8 142.9
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