# Class 07: Topic 6: Two-Way Tables

This outline is also available in PDF.

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.

Overview:

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

## 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
This document may be found at `http://www.cs.grinnell.edu/~rebelsky/Courses/MAT115/2008S/Outlines/outline.07.html`.
Copyright © 2008 Samuel A. Rebelsky. This work is licensed under a Creative Commons Attribution-NonCommercial 2.5 License. To view a copy of this license, visit `http://creativecommons.org/licenses/by-nc/2.5/` or send a letter to Creative Commons, 543 Howard Street, 5th Floor, San Francisco, California, 94105, USA.