Graphical Misrepresentations of Data

1
Lesson 2 - 4

• Graphical Misrepresentations of Data

2
Objectives

• Describe what can make a graph misleading or
  deceptive

3
Vocabulary

• None New

4
Common problems

• Vertical Axis
• Inconsistent vertical scaling
• Incorrect vertical scaling
• Vertical axis that doesnt start at zero
• Scaling in pictures different than that reflected
  by the data
• Class widths
• Values overlap
• Class widths different

5
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6
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7
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8
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9
Characteristics of Good Graphics

• Label the graphic clearly and provide
  explanations if needed
• Avoid distortion. Dont lie about the data
• Avoid three-dimensions. Look nice, but often
  distract reader and result in misinterpretation
• Dont use more than one design in the same
  graphic.
• Let the numbers speak for themselves
• Sometimes graphs use a different design in a
  portion of the graphic to call attention to it

10
Summary and Homework

• Summary
• Good graphs speak for themselves
• Avoid well-intended, but misleading flaws
• Homework
• pg 107-109 1, 2, 7, 8, 13, 14