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Grade 9-12
,
Lesson

When Graphs Mislead Us

Updated: January 7 2016,
Open Lesson

Assessment Activity

Multiple Choice

  1. What is misleading in the graph below?

  1. Title
  2. Origin
  3. Unit
  4. [Scale]
  1. Which two of the following would be used to determine a country’s standard of living?

Country

Infant Mortality Rate (per 1,000 live births)

Population (in millions)

Real GDP (in millions of U.S. Dollars)

Life Expectancy

Australia

4

22.3

    922,870

82

Finland

3

5.4

    390,407

80

Germany

3

81.8

3,204,596

81

Japan

2

126.5

4,383,325

83

  1. Infant mortality and population
  2. Life expectancy and real GDP
  3. [Population and real GDP]
  4. Real GDP and infant mortality

(NOTE: Data from FRED, 2011)

  1. Which of the following graphs might lead people to incorrectly conclude that “college students eat twice as much pizza as tacos”?

[Answer B.]

Constructed Response

The Dow Jones Industrial Average is considered by some to be a vital sign of the health of the U.S. stock markets. Below are two tables showing the Dow Jones Industrial Average. Compare and contrast the two graphs. If a person only saw Graph 2, what might they assume about the Dow Jones Industrial Average? Explain.

Graph 1:

Graph 2:

Sample answer: the two graphs are similar because they show the Dow Jones Industrial Average (DJIA) over a period of time, they both use index as the unit on the Y-axis, and they both have the same title. The graphs are different because they have different origins on each axis, cover a different time period, and have different increments on each scale. Graph 2 primarily shows a decline in the Dow Jones Industrial Average. Given the limited number of years shown (2007 to 2009) one might assume that the DJIA only decreases over time. 

Overview

Becoming a good consumer of information means being able to determine whether graphs are misleading. To do so, students must learn the components of a graph and how to tell whether they as readers are being manipulated to serve a specific point of view. Just like vital signs determine the health of a person, data about a country can show its health. Specifically, a country’s material standard of living is directly proportional to its real Gross Domestic Product per capita. In other words, if a country has a high real GDP per capita, it also has a high standard of living.

Sources

Gross domestic product and Dow Jones Industrial Average graphs created using Federal Reserve Economic Data (FRED) available at: www.research.stlouisfed.org/fred2/