Week 5 Preparation and Overview | Thinking Critically About Data Presented in Graphs

Purpose

To assess your ability to:

• Identify the basic types of graphs.
• Analyze and evaluate graphs.

Overview

In this LAB assignment, you will need to construct your own answers based on the video links, the readings from the key points for this week, and CHAPTER #7 of Mark Battersby s Is that a fact? A field guide to statistical and scientific information.

Misleading Graphs

SUMMARY

The common ways to make a graph misleading are:

• Scale not starting at zero.
• Scale made very small to make the graph look very big.
• Scale values or labels missing from the graph.
• Incorrect scale placed on the graph.
• Pieces of a Pie Chart are not the correct sizes.
• Oversized volumes of objects that are too big for the vertical scale differences they represent.
• Size of images used in Pictographs being different for the different categories being graphed.
• Graph being a non-standard size of shape.

Posted by Passy s World of Mathematics (http://passyworldofmathematics.com/misleading-graphs/)

Action Items

1. Choose five (different) basic types of (non-misleading) graphs and explain, in your own words, how they are used to make sense out of data. Please refer to Part 1 of the key points from Week 6.
2. Given the summary list of misleading graphs (see the overview), use Internet, newspaper, or magazine sources to locate an appropriate example of each type of the misleading graphs (you should have eight, each corresponding to an item in the list). Each graph can be taken from a cartoon, an article, or advertisement.

Note: As an alternative, you may also construct your own graphs.

3. Explain why each graph you chose or created illustrates the corresponding deceptive practice on the list.
4. From Action Item #2 above, choose only one graph from the ones you found and use the four critical questions to fully analyze and evaluate it.
5. Be sure to answer the four basic CRITICAL QUESTIONS applied to graphs (p.97 of the textbook):
   1. What is being claimed?
   2. How good is the evidence?
   3. What other information is relevant?
   4. Are relevant fallacies avoided? (e.g., fallacies of Inappropriate Proportions, Misleading Scales, Varying Scales on One Axis, Misleading Comparisons, Misleading Visual Impressions, etc.).
6. Cite your sources, including for all of the examples of graphs you find.
7. Complete Action Items 1 - 6 in a Microsoft Word document.