sol-midterm.pdf - Midterm Exam Solutions Problem 1 The...

Midterm Exam Solutions
Problem 1: The distribution by age in the U.S. in 2004 is given in the table below.
(1) Draw the corresponding histogram. Notice that the class intervals include the left
endpoint, not the right one. The interval for “75 and over” can be ended at 85.
(4 pts)
(2) Are there more 23-year-olds, or more age 63-year-olds?
(1.5 pts)
(3) Is the percentage of people age 35 or more around 25%, 50% or 75%?
(1.5 pts)
Age % of population Age % of population
0–5 7 35–45 15
5–15 14 45–55 14
15–20 7 55–65 10
20–25 7 65–75 6
25–30 7 75 and over 6
30–35 7
(1). See Figure 1 for drawing of the histogram.
(2). There are more 23 year old. Since the age between 20 and 25 occupies
7% of the population and the age between 55 and 65 occupies 10% of the popu-
lation. So on average, 23 year old amount to 1.4% while 61 year old amount to
1.0%.
(3). The percentage of people age 35 or more is around 50% judging by the
histogram.