Overview
Students look at real-life graphs to determine why they are misleading.
Objective
Students will be able to correct a graph that is drawn incorrectly and describe why it is incorrect.
Standards Addressed
Mathematics — Data Analysis Grade 7 Statistical Methods, Benchmark G 06. Identify misuses of statistical data in articles, advertisementsand other media.
Mathematics — Data Analysis
Grade 7
Statistical Methods, Benchmark G 06. Identify misuses of statistical data in articles, advertisementsand other media.
Statistical Methods, Benchmark G
06. Identify misuses of statistical data in articles, advertisementsand other media.
Procedure
Talk about how a graph helps to make data easy to understand.
Distribute the student handouts.
Review the handout CNN and the Schiavo Case with the students. Have them study the graph and discuss why it is misleading.
Answer: The vertical axis does not begin with zero, so the difference shown leads you into thinking that the difference is great.
Ask students to draw the graph correctly. They will see the difference when they make the graph with zero as the origin of both the x and the Y axes.
Have students look at the following graphs and write a sentence or two as to why they are misleading.
Answers: Graph #1 — The x-axis is fine, but the y-axis has inconsistent intervals. Graph #2 — The pictures in the graph are not of equal size. It looks as if there are more people who have horses as pets.
Answers: Graph #1 — The x-axis is fine, but the y-axis has inconsistent intervals.
Graph #2 — The pictures in the graph are not of equal size. It looks as if there are more people who have horses as pets.
Evaluation
Evaluation could be done as a class where students share their reasons why the graphs are misleading, or points could be given if answers are correct.
