Chapter 3 Review Exercises, p. 50, #1 – 4 all, and 6, 7
1. Heights between 66 and 72 inches.
2. To find the height of each rectangle for each class interval,
Age
% of population
% per year (the height of the rectangle)
0–5
8
8 / 5 = 1.6
5 – 14
13
13 / 9 = 1.4
14 – 18
5
5 / 4 = 1.25
18 – 25
10
10 / 7 = 1.43
25 – 30
8
8 / 5 = 1.6
30 – 35
9
9 / 5 = 1.8
35 – 45
16
16 / 10 = 1.6
45 – 55
10
10 / 10 = 1
55 – 65
8
8 / 10 = 0.8
65 – 75
7
7 / 10 = 0.7
75 and over
5
5 / 10 = 0.5 (Since the book said to end at 85)
I will need to put the actual histogram on the overhead projector in class. (Remind me if I don’t.)
a. There are more children age one (1.6 %), than age eleven (1.4 %).
b. There are more 31 year olds (1.8 %) than 21 year olds (1.43 %).
c. Looking at the group blocks (area): More are age 35 – 44 (16 %), than age 30 – 34 (9 %).
d. The percentage of people age 32 or more looks to cover about half the histogram, or 50 %.
3. Again, this histogram will need to be put on the overhead projector in class.
a. When rates are rounded off, they may not add up to exactly 100 %.
b. No. Percent gives the rate, so it adjusts for any difference in the numbers. One-room
apartments are cheaper and easier to rent for those who can’t afford more.
c. Owner-occupied units are larger (the histogram is shifted to the right).
4. a.
b.
c.
d.
e.
The percentage of women with blood pressure above 130 is about 25 % (1/ 4 of the area).
The percentage is about 99 % because it is almost all of the area.
More women are in the 140 – 150 mm interval, since the area of that rectangle is larger.
The 135 – 140 mm interval is taller, so that interval is more dense/ more crowded.
The height is 2.1 % per mm, the width is 5 mm (from 130mm – 125 mm), so this class interval
is 10.5 % (the area of the rectangle).
f. Both intervals are one unit wide, so the taller one will have more: 102 – 103 mm.
g. The most crowded mm is the tallest one. The answer is any mm in the 115 – 120 range; for
example, the 117 – 118 mm.
5. Omit
6. Both (i) and (ii) have one-fourth of the people between 66.5 and 67.5 inches, half the people
between 67.5 and 68.5 inches, and one-fourth of the people between 68.5 and 69.5 inches. For
(iii), the percentages were 30 %, 40 %, and 30 %, not 25 %, 50 %, and 25 %.
7. Death from natural causes will tend to be the older people, so it is histogram (i). Death from
accidents and other trauma tends to be younger people, so it is histogram (ii).