6th Grade Math Textbook, Progress

Misleading Graphs and Statistics

9-12

Use the graphs above for exercises 1–2.

1. It is time for a new labor contract. 2. Why does the bar graph give the
   Which line graph would you use impression that gerbil food sales are
   if you represented labor? Which about 6 times as great as hamster
   would you use if you represented food sales? Draw an accurate bar
   management? Explain. graph for the data.

When data presented in a graph affects the impression the graph makes, the

representation is considered biased. Examine the two graphs below.

Both graphs show the same information about worker hourly pay.

Although both show that wages have increased, the graph at

the right gives the impression that wages have increased more

rapidly. What causes this?

Look at the vertical scale of each graph. The expanded scaleon the

graph at the right creates the impression of a faster rate of increase.

Study this example.

This graph is misleading. Although

gerbil food sales are twicethose

of hamster food sales, the graph

gives the impression that the

difference is much greater because

the scale does not start at 0.

0

2002 2003 2004 2005

2

4

6

8

10

Hourly Pay (dollars)

Year

Worker Wages

0

2002 2003 2004 2005

4

5

6

Hourly Pay (dollars)

Year

Worker Wages

Pet Food

Hamster

Gerbil

8 10 12 14 16

Number of Cases Sold

18 20 22 24

Pet Food Sales

2.3

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