66 CHAPTER 2 Descriptive Statistics Extending Concepts A Misleading Graph? A misleading graph is not drawn appropriately, which can misrepresent data and lead to false conclusions. In Exercises 37– 40, (a) explain why the graph is misleading, and (b) redraw the graph so that it is not misleading. 37. Quarter 1st 2nd 3rd 4th 90 100 110 120 Sales (in thousands of dollars) Sales for Company A 38. Type of student High school Middle school College/ university 56 60 64 68 72 Percent that responded “yes” Results of a Survey 39. 1st quarter 38% 4th quarter 20% 3rd quarter 38% 2nd quarter 4% Sales for Company B 40. Non-OPEC countries OPEC countries 500 1000 1500 2000 Barrels (in millions) U.S. Crude Oil Imports by Country of Origin, January−December 2020 (Source: U.S. Energy Information Administration) 41. Law Firm Salaries A back-to-back stem-and-leaf plot compares two data sets by using the same stems for each data set. Leaves for the first data set are on one side while leaves for the second data set are on the other side. The back-to-back stem-and-leaf plot at the left shows the salaries (in thousands of dollars) of all lawyers at two small law firms. (a) What are the lowest and highest salaries at Law Firm A? at Law Firm B? How many lawyers are in each firm? (b) Compare the distribution of salaries at each law firm. What do you notice? 42. Yoga Classes The data sets at the left show the ages of all participants in two yoga classes. (a) Make a back-to-back stem-and-leaf plot as described in Exercise 41 to display the data. (b) What are the lowest and highest ages of participants in the 3:00 p.m. class? in the 8:00 p.m. class? How many participants are in each class? (c) Compare the distribution of ages in each class. What observation(s) can you make? 43. Choosing an Appropriate Display Use technology to create (a) a stem-and-leaf plot, (b) a dot plot, (c) a pie chart, (d) a frequency histogram, and (e) an ogive for the data. Which graph displays the data best? Explain. 64 46 40 55 70 31 47 44 55 63 49 49 26 72 64 55 44 71 45 72 Law Firm A Law Firm B 5 0 9 0 3 85222 10 57 99700 11 005 11 12 0335 13 2 2 5 9 14 13339 15 5 5 5 6 16 4 9 9 99510 17 125 55521 18 9 99875 19 0 3 20 Key: 50 190 0 = $195,000 for Law Firm A and $190,000 for Law Firm B FIGURE FOR EXERCISE 41 3:00 P.M. class 8:00 P.M. class 40 60 73 77 51 68 68 35 68 53 64 75 76 69 59 55 38 57 68 84 75 62 73 75 85 77 19 18 20 29 39 43 71 56 44 44 18 19 19 18 18 20 25 29 25 22 31 24 24 23 19 19 18 28 20 31 TABLE FOR EXERCISE 42
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