Grade 8, Vol 2 Math Student Handbook

Sessions 21 & 22 (cont.) Math: Statistics & Probability: Graphs

MISLEADING GRAPHS

Graphs can be a powerful way to share data with the public. But not all graphs are created equal. Choosing the wrong graph type, mislabeling axes, or using an inappropriate or inconsistent scale can affect the way data appears—which can lead readers to misinterpret the data.

EXAMPLE: How is the graph below misleading? What argument might someone who created the graph want to make?

Analyze It

Look for clues like the wrong graph type, mislabeled axes, or a scale that’s too big or small.

CAREERS TEENS SAY THEY WANT TO PURSUE

100 120 140 160

CAREERS TEENS SAY THEY WANT TO PURSUE

40 60 80 100 120 140 160

DOCTOR

ATHLETE

TEACHER

SCIENTIST

CAREER

40 60 80

CAREERS TEENS SAY THEY WANT TO PURSUE

150

Here’s what we did to fix it: We started the y -axis scale at 0 and made sure all bars follow it. More respondents do want to pursue a career as a scientist instead of as an athlete but the difference isn’t as dramatic as the original graph depicts. 120 SCIENTIST TEACHER DOCTOR ATHLETE

Check It

CAREER

90

CAREERS TEENS SAY THEY WANT TO PURSUE

30 120 60 150

0 90

DOCTOR

ATHLETE

TEACHER

SCIENTIST

CAREER

60

30

0

DOCTOR

ATHLETE

TEACHER

SCIENTIST

CAREER

62 Sessions 21 & 22

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