Class 07: Topic 6: Two-Way Tables

Held: Wednesday, 6 February 2008

Summary: We begin our in-depth exploration of the ways in which you might provide summary information of data gathered in experiments or observational studies.

Notes:

• Homework for Friday: Activities 6-6, 6-10, 6-26, 6-30 [cancelled].
• Also prepare topic 7.
• Because there's a lot of analysis and graphing today, there are some R tips available as handouts.

• Handouts: GenderedPLAs.csv, Stacked Bar Graphs in R, R notes on activity 6-1, R notes on activity 6-3.
• Due: Activities 5-8, 5-10, 5-12, 5-16, 5-25, 5-27, 5-28.

Overview:

• Summary of Unit 1.
• Looking ahead to Unit 2.
• Topic 6: Two-Way Tables

Summary of Unit 1

Looking Ahead to Unit 2

Topic 6: Two-Way Tables

• The question: How do I report on the effect of a categorical variable on another categorical variable?
  • Particularly when there are only a few values for each variable.
• Textual solution: Two-way tables.
• Graphical solution: Stacked bar charts.

Activities for Topic 6

• Do the activities (or at least as many as you can complete).
• Handouts to help with the parts that can use R.
• Data for 6-3 distributed, too.
• In the last few minutes of class we'll return to a few key ideas
  • Is 6-3 an experiment or observational study?
  • Organizing two-way tables
  • Simpson's paradox