Questions | Answer Key

Practice Exercise 17-3 Click HERE for a printer-friendly version

Before going further to learn about functions as graphs in the coordinate system, please try these review problems. When you finish, compare your answers to those in the key that follows.

  1. According to the U.S. Census bureau, the number of births in 1998 to unmarried women was, by age group:2

15 to 19

381,000

20 to 24

460,000

25 to 29

243,000

30 to 34

125,000

35 to 39

61,000

Represent that data with a histogram.

  1. The results on a math exam in a class of 25 students are as follows:
99 42 91 66 60 70 64 70 61 75 82 65 68
39 77 81 73 74 94 54 83 71 73 72 66

Use a histogram with intervals of width 10, starting with the interval 30-39, to graphically represent these results.

  1. Examine the data in the example above again. Notice that by using intervals of width 10, going from age 6 to age 85, there were several age intervals that had one or zero people. If you look at the response data, you can see that the responses for age ranged from 15 to 62. Create a couple of different histograms that use different interval widths and starting points so that there aren’t any blank intervals.

#

Age
1 

15
 2

44
 3

32
 4

33
 5

27
 6

22
 7

47
 8

62
 9

25
 10

22
 11

21
 12

43
 13

18
 14

19
 15

21
 16

25
 17

29
 18

31
 19

24
 20

27

Now, correct Practice Exercise 17-3 using the Answer Key below.

Answer Key (Click HERE for a printer-friendly version) (top)

  1.  

Births to unmarried women (thousands)     

  1.  

 

  1. Note that the age range of 15 to 63 is 48 years wide [63 minus 15]. One way is to split the 48 years into 8 intervals, each 6 years wide, starting at age 15. That results in the following histogram

Another reasonable approach is to split the 48 years into 5 intervals of 10 years each, and since the lowest age is 15, that will result in aesthetic endpoints [15, 25, 35, 45, 55, 65]

The slight disadvantage is that the intervals are quite wide, so we don’t have much detail about the way the students are distributed, which is especially a problem in the 15 to 35 range. Reverse the last idea, so make 10 intervals each 5 wide, getting a much more detailed histogram:

2 http://www.census.gov/prod/2001pubs/statab/sec02.pdf

 

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