ANSWERS A-43 15. a) 2 4 6 8 10 12 14 16 2 4 6 8 101214 y x b) 0.999 c) Yes d) Yes 17. a) 20 1 2 3 4 5 6 7 8 40 60 80 100 y x b) 0.968 − c) Yes d) Yes 19. Yes 21. No 23. Yes 25. No 27. y x 1.26 3.51 = + 29. y x 0.18 24.82 = + 31. y x 0.81 5.84 = + 33. y x 0.08 9.50 = − + 35. a) 0.987 b) Yes c) y x 1.58 2.91 = + d) 19 minutes 37. a) 0.979 − b) Yes c) y x 1.07 83.30 = − + d) ≈48 cups 39. a) 0.961 b) Yes c) y x 0.20 1.05 = − d) $3.95 41. a) 0.993 b) Yes c) y x 3.90 1.94 = + d) 21 ≈ kilocalories 43. a) Answers will vary. b) Answers will vary. c) 60 100 150 200 250 300 65 70 75 80 Dry Pavement Stopping Distance (ft) Speed (mph) 60 250 300 350 400 450 500 550 600 650 65 70 75 80 Wet Pavement Stopping Distance (ft) Speed (mph) d) 0.999 e) 0.990 f) Answers will vary. g) y x 5.36 183.40 = − h) y x 16.22 669.80 = − i) Dry, 229.3 ft; wet, 579.1 ft 45. a) Correlation will not change. b) Answers will vary. 47. a) Answers will vary. b) Answers will vary. c) Answers will vary. d) Answers will vary. e) Answers will vary. f) Answers will vary. g) Answers will vary. 49. a) 0.922 ≈ b) Should be the same. REVIEW EXERCISES, PAGE 838 1. a) A population consists of all items or people of interest. b) A sample is a subset of the population. 2. a) A random sample is one where every item in the population has the same chance of being selected. b) A systematic sample is obtained by selecting a random starting point and then selecting every nth item in a population. 35. a) Answers will vary. b) Answers will vary. c) MLB: $37.8 million, NFL: $46.2 d) MLB: $3.4 million, NFL: $4.3 million 37. Answers will vary. SECTION 12.5, PAGE 818 1. Rectangular 3. a) Right b) Left 5. Bell 7. 0 9. a) 68% b) 95% c) 99.7% 11. Answers will vary. 13. Answers will vary. 15. a) 1 b) 1− c) 1.5 d) 2.5 − 17. Normal 19. Skewed right 21. Bimodal 23. Rectangular 25. 0.5000 27. 0.8185 29. 0.9925 31. 0.0143 33. 0.9878 35. 0.0429 37. 58.87% 39. 97.13% 41. 93.24% 43. 0.88% 45. 21.96% 47. a) Luisa, Sarah, Eleanor b) Jenny, Shenice c) Sadaf, Heather, Kim-Liu 49. 50% 51. 50% 53. 81.85% 55. ≈53 adults 57. 69.15% 59. 86.64% 61. 10.56% 63. 93.32% 65. 59.87% 67. 50% 69. 11.51% 71. ≈23 cars 73. 25.1% 75. ≈187 females 77. 27.43% 79. 0.62% 81. ≈83 families 83. 8.23% 85. The standard deviation is too large. 87. a) B b) C c) A 89. The mean is the greatest value. The median is lower than the mean. The mode is the lowest value. 91. Answers will vary. 93. a) Katie: z 2.4; = Stella: z 1.7 = b) Katie. Her z-score is higher than Stella’s z-score, which means her sales are further above the mean than Stella’s sales. 95. 1.18 − 96. Answers will vary. 97. 2 SECTION 12.6, PAGE 832 1. Coefficient 3. a) 1 b) 1− c) 0 5. Positive 7. No correlation 9. Strong positive correlation 11. a) 2 4 6 8 10 12 14 16 2 4 6 8 10 12 y x b) 0.981 c) Yes d) Yes 13. a) 5 10 15 20 25 30 35 40 20 25 30 35 40 45 50 y x b) 0.228 c) No d) No
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