1
Homework 2 answer key
3.1.
The figure below shows a histogram for the heights of a representative sample of
men. The shaded area represents the percentage of men whose heights were between
________ and _________. Fill in the blanks.
% per
20
inch
10
0
58
60
62
64
66
68
70
72
74
76
78
80
HEIGHT (Inches)
66
inches
and 72 inches
3.2.
The distribution by age in the United States in 1991 is shown below. Draw the
histogram. (The class intervals include the left endpoint, not the right; for instance, on the
second line of the table, 13% of the people were age 5 years or more but had not yet
turned 14. The interval for “75 and over” can be ended at 85. Men and women are
combined in the data.) Use your histogram to answer the following questions.
Age
Percent of Population
Density =%/class width
05
8
1.6
514
13
1.44
1418
5
1.25
1825
10
1.43
2530
8
1.6
3035
9
1.8
3545
16
1.6
4555
10
1
5565
8
0.8
6575
7
0.7
75 and over
5
0.5
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% population
per year
1
0
10
20
30
40
50
60
70
80
90
AGE (in years)
(a)
Are there more children at age 1, or more at age 11?
When we draw a density histogram, the area under a block, e.g.
under the block corresponding to class interval 05 is divided
equally among the subintervals within that interval. Based on
that, the area corresponding to 1 is larger than the area
corresponding to 11 (higher density for 1 than for 11).
(b)
Are there more 21yearolds, or more 31yearolds?
More at 31. Density is higher for 31 years old (i.e, percentage of population 31
yearold is higher than percentage population 21yearsold.
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 Spring '08
 FRATTO
 Statistics, Histogram, Percentage point

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