768 APPENDIX D 5. Class width: 10. Class midpoints: 24.5, 34.5, 44.5, 54.5, 64.5, 74.5, 84.5. Class boundaries: 19.5, 29.5, 39.5, 49.5, 59.5, 69.5, 79.5, 89.5. Number: 91. 7. Class width: 100. Class midpoints: 49.5, 149.5, 249.5, 349.5, 449.5, 549.5, 649.5. Class boundaries: -0.5, 99.5, 199.5, 299.5, 399.5, 499.5, 599.5, 699.5. Number: 153. 9. No. The maximum frequency is in the second class instead of being near the middle, so the frequencies below the maximum do not mirror those above the maximum. 11. Yes. Except for the single value that lies between 600 and 699, the frequencies start low, reach a maximum of 90, and then decrease. The values below the maximum are very roughly a mirror image of those above it. (That single value between 600 and 699 is an outlier that makes the determination of a normal distribution somewhat questionable, but using a loose interpretation of the criteria for normality, it is reasonable to conclude that the distribution is normal.) 13. The data amounts do not appear to have a normal distribution. The distribution does not appear to be symmetric because the frequencies preceding the maximum frequency of 16 are far outweighed by the frequencies following the maximum. Daily Commute Time in Chicago (Minutes) Frequency 0–14 5 15–29 16 30–44 14 45–59 9 60–74 5 75–89 1 3. Daily Commute Time in Boston (minutes) Relative Frequency 0–29 46.8% 30–59 42.2% 60–89 9.2% 90–119 1.0% 120–149 0.8% 15. Duration (sec) Frequency 125–149 1 150–174 0 175–199 0 200–224 3 225–249 34 250–274 12 17. Burger King Lunch Service Times (sec) Frequency 70–109 11 110–149 23 150–189 7 190–229 6 230–269 3 19. The distribution does appear to be a normal distribution. Weight (kg) Frequency 40–49 2 50–59 22 60–69 23 70–79 13 80–89 3 90–99 4 21. Because there are disproportionately more 0s and 5s, it appears that the heights were reported instead of measured. It is likely that the results are not very accurate. Last Digit Frequency 0 9 1 2 2 1 3 3 4 1 5 15 6 2 7 0 8 3 9 1 23. The actresses appear to be generally younger than the actors. Age (yr) Actresses Actors 20–29 34.1% 1.1% 30–39 37.4% 31.9% 40–49 16.5% 41.8% 50–59 3.3% 17.6% 60–69 6.6% 6.6% 70–79 1.1% 1.1% 80–89 1.1% 0.0% Age (yr) of Best Actress When Oscar Was Won Cumulative Frequency Less than 30 31 Less than 40 65 Less than 50 80 Less than 60 83 Less than 70 89 Less than 80 90 Less than 90 91 25.
RkJQdWJsaXNoZXIy NjM5ODQ=