1. Displaying Distributions – Qualitative Variables
Lecture 14
Sections – 4.3.2
Fri, Feb 9, 2007

2. Pie Charts
Pie chart.
Use the percentage associated with the category to compute the central angle of the pie slice.
E.g., 25% of 360 = 90.
A pie chart facilitates the comparison of one category to the whole.

3. Example Meet Pie-Chart Pam. What does the pie chart tell us?
Make a pie chart of the political affiliations at UNC-Chapel Hill.
What does the pie chart tell us?
Is a pie chart an appropriate display of these data?

4. Bar Graphs
Bar graph.
A bar graph facilitates the comparison of one category to another.
Bar graph of political affiliation.

5. Example Pie-Chart Pam also does bar graphs. What does it tell us?
Make a pie chart of the political affiliations at UNC-Chapel Hill.
What does it tell us?
Is a bar graph an appropriate display of these data?

6. Pie Chart Examples Where Your Income Tax Money Really Goes
Major Religions of the World Ranked by Number of Adherents
Warning against using piecharts