Study Guide and Intervention (continued) - MathnMind

13-3
NAME ______________________________________________ DATE ____________ PERIOD _____
Study Guide and Intervention
Histograms
Interpret Data in Histograms A histogram is a bar graph in which the data are
organized into equal intervals. In a histogram, the horizontal axis shows the range of data
values separated into measurement classes, and the vertical axis shows the number of
values, or frequency, in each class.
Example
SCHOOL Answer each question
about the histogram shown.
a. In what measurement class does the
median occur?
First add the frequencies to determine the
number of state scores:
1 1 6 12 24 7 51. There are
51 scores. Therefore, the middle data value is the
26th value. The median value is in the 21.1–22.1
measurement class.
b. Describe the distribution of the data.
• Only two states have a composite score less than 19.1.
• Almost half of the states have a composite score in the 21.1–22.1 range.
• More than half of the states have a composite score above 21.1.
• The distribution is skewed to the right.
Exercises
For each histogram, answer the following.
• In what measurement class does the median occur?
• Describe the distribution of the data.
1. 2.
Frequency
Record Lowest Temperature (Celsius)
25
20
15
10
5
0
70–
60 60–
50 50–
40 40–
30 30–
20 20–
by State*
10
Celsius Temperature
*Includes Washington, DC
Source: Almanac 2001
20
15
10
5
0
15–25 25–35 35–45 45–55 55–65
Age (years)
© Glencoe/McGraw-Hill 793 Glencoe Algebra 1
Frequency
(millions)
ACT Average Composite Scores, 2001
by State*
25
20
15
10
5
0
17.1– 18.1– 19.1– 20.1– 21.1– 22.1–
18.1 19.1 20.1 21.1 22.1 23.1
Score
*Includes Washington, DC
Frequency
Source: www.act.org
Hourly U.S. Workers, 2000
Source: The World Almanac
Lesson 13-3