110 CHAPTER 2 Descriptive Statistics Graphical Analysis In Exercises 19–22, use the box-and-whisker plot to determine whether the shape of the distribution represented is symmetric, skewed left, skewed right, or none of these. Justify your answer. 19. 0 40 80 120 160 200 20. 20 30 40 50 60 70 80 90 21. 30 40 50 60 70 80 90 100 110 22. 100 200 300 400 500 600 Using Technology to Find Quartiles and Draw Graphs In Exercises 23–26, use technology to draw a box-and-whisker plot that represents the data set. 23. Studying The number of hours spent studying per day by a sample of 28 students 2 8 7 2 3 3 3 2 2 7 8 3 5 1 1 2 6 1 5 7 3 8 5 3 3 7 6 2 24. Vacation Days The number of vacation days used by a sample of 20 employees in a recent year 3 9 2 1 7 5 3 2 2 6 4 0 10 0 3 5 7 8 6 5 25. Commuting Distances The commuting distances (in miles) of a sample of 30 employees 7 6 7 5 2 1 1 2 3 8 15 24 3 8 9 19 12 17 45 4 4 3 11 26 10 4 21 1 5 12 26. Hourly Earnings The hourly earnings (in dollars) of a sample of 21 employees at a consulting firm 25.89 27.09 31.76 28.28 26.19 27.43 24.06 25.61 22.56 29.76 18.01 23.66 38.24 37.27 32.70 31.12 25.87 15.06 23.12 30.62 19.85 27. Studying Refer to the data set in Exercise 23 and the box-and-whisker plot you drew that represents the data set. (a) About 75% of the students studied no more than how many hours per day? (b) What percent of the students studied more than 3 hours per day? (c) You randomly select one student from the sample. What is the likelihood that the student studied less than 2 hours per day? Write your answer as a percent. 28. Hourly Earnings Refer to the data set in Exercise 26 and the box-and-whisker plot you drew that represents the data set. (a) About 50% of the employees made less than what amount per hour? (b) What percent of the employees made more than $23.39 per hour? (c) What percent of the employees made between $23.39 and $38.24 per hour? (d) You randomly select one employee from the sample. What is the likelihood that the employee made more than $30.87 per hour? Write your answer as a percent.
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