12. The Quick Change Oil Company has a number of outlets in the metropolitan Seattle area. The daily number of oil changes at the Oak Street outlet in the past 20 days are: The data are to be organized into a frequency distribution. a. How many classes would you recommend?
b. What class interval would you suggest?
Describing Data: Frequency Tables, Frequency Distributions, and Graphic Presentation 35 on 12.8 percent of the vehicles sold is between $1,000 and $1,400. The relative fre-
quencies for the remaining classes are shown in Table 2–8.
TABLE 2–8 Relative Frequency Distribution of Profit for Vehicles Sold Last Month at Applewood Auto Group
Profit Frequency Relative Frequency Found by
$ 200upto$ 600 8 .044 8180
600 up to 1,000 up to 1,400 up to 1,800 up to 2,200 up to 2,600 up to 3,000 up to
Total
1,000 11 1,400 23 1,800 38 2,200 45 2,600 32 3,000 19 3,400 4
.061 11180 .128 23180 .211 38180 .250 45180 .178 32180 .106 19180 .022 4180
180 1.000
27 27 27 28 27 25 25 28 26 28 26 28 31 30 26 26
65 98 55 62 79 59 51 90 72 56 70 62 66 80 94 79 63 73 71 85
36
Chapter 2
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LO6 Present data from a frequency distribution in a histogram or a frequency polygon.
c. What lower limit would you recommend for the first class?
d. Organize the number of oil changes into a frequency distribution.
e. Comment on the shape of the frequency distribution. Also determine the relative fre-
quency distribution.