Interpreting Data: Muddying the Waters

Mathematical goals

This lesson unit is intended to help you assess how well students are able to:

  • Interpret data and evaluate statistical summaries.
  • Critique someone else’s interpretations of data and evaluations of statistical summaries.

The lesson also introduces students to the dangers of misapplying simple statistics in real-world contexts and illustrates some of the common abuses of statistics and charts found in the media.


This lesson unit is structured in the following way:

  • In the first lesson, students work individually on a task designed to reveal their current understanding. You review their solutions, creating questions to help them to improve their work.
  • During the second lesson, students role-play a scene that provides the background to the lesson task. Next, students work in small-groups on a collaborative discussion task. They extract information from evidence and critically assess how it was gathered and presented.
  • After a whole-class discussion students work alone on a new task, similar to the original task.

Materials required

  • Each student will need a copy of Muddying the Waters and Unhappy Campers.
  • Each small group of students will need a copy of the role-play script A Case of Muddying the Waters and the Case Notes worksheet.
  • There is a projector resource to support the role-play and whole-class discussion. Use of a computer and projector is recommended. You could print the images onto overhead projector slides instead. If you do not have access to a projector, print a copy of Slides Exhibits 1, 2, 3, 4, Scene 1: The Assistant DA’s office, and Scene 2: At the Factory for each small group of students.
  • A teaspoon may be useful to help illustrate the concept of ‘mg per cubic meter’.

Time needed

30 minutes before the lesson, a 1-hour lesson, and 15 minutes in a follow-up lesson. All timings are approximate. Exact timings will depend on the needs of the students.