A56 ODD ANSWERS 11. Number of stories Height (in feet) Heights of Buildings 10001200 1400 1600 1800 50 60 70 80 90 100 110 Sample answer: The number of stories appears to increase with height. 13. x = 29.85; median = 29.75; mode = 30.0 15. 82.1 17. 38.4 19. Skewed right 21. Skewed right 23. Mean; When a distribution is skewed right, the mean is to the right of the median. 25. Range = 14; m ≈ 6.9; s 2 ≈ 21.1; s ≈ 4.6 27. Range = $2044; x ≈ $6266.81; s2 ≈ 455,944.30; s ≈ $675.24 29. $75 and $145 31. 30 customers 33. x ≈ 2.5; s ≈ 1.2 35. CVfreshmen ≈ 41.3%; CVseniors ≈ 24.2% Grade point averages are more variable for freshmen than seniors. 37. Min = 22, Q1 = 30, Q2 = 35.5, Q3 = 58, Max = 141 39. 15 30 60 90 120 45 75 105 135 150 35.5 22 30 58 141 Fuel economy (in miles per gallon) Model 2020 Vehicle Fuel Economies 41. 1 inch 43. 35% 45. Not unusual; The z-score is 1.97, so a towing capacity of 16,500 pounds is about 1.97 standard deviations above the mean. 47. Unusual; The z-score is 2.60, so a towing capacity of 18,000 pounds is about 2.60 standard deviations above the mean. Quiz for Chapter 2 (page 120) 1. (a) Class Midpoint Class boundaries 101 – 112 106.5 100.5–112.5 113 – 124 118.5 112.5–124.5 125 – 136 130.5 124.5–136.5 137 – 148 142.5 136.5–148.5 149 – 160 154.5 148.5–160.5 Frequency, f Relative frequency Cumulative frequency 3 0.11 3 11 0.41 14 8 0.30 22 3 0.11 25 2 0.07 27 (b) Number of minutes Frequency 10 8 6 4 2 94.5 106.5 118.5 130.5 142.5 154.5 166.5 Weekly Exercise (c) Number of minutes Relative frequency 0.40 0.32 0.24 0.16 0.08 106.5 118.5 130.5 142.5 154.5 Weekly Exercise (d) Skewed right (e) Number of minutes Cumulative frequency Weekly Exercise 112.5 124.5 100.5 136.5 148.5 160.5 5 10 15 20 25 30 (f) Weekly Exercise (in minutes) 10 1 8 Key: 100 8 = 108 11 1 4 6 7 8 9 9 12 0 0 3 3 4 7 7 8 13 0 1 1 2 5 9 9 14 2 15 0 7 (g) 100 110 120 130 140 150 160 101 118 124 132 157 Number of minutes Weekly Exercise 2. x ≈ 126.1; s ≈ 13.0 3. (a) Elements with Known Properties Metalloids 5.5% Halogens 4.6% Noble gases 5.5% Rare earth elements 27.5% Other nonmetals 6.4% Metals 50.5%
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