Chapter 12 - 2: Experiments with more than one independent variable

In this chapter we'll cover the following learning objectives:

1. Articulate how a factorial design works.

2. Explain two reasons to conduct a factorial study.

3. Review studies with one independent variable, which show a simple "difference."

4. Describe an interaction as a "difference in differences."

5. Describe interactions using terms such as "it depends" or "especially for."

6. Estimate marginal means in a factorial design, to look at main effects.

7. Identify interaction effects two ways: in a table and in a graph.

8. Given a factorial notation (e.g., 2×2), identify the number of independent variables, the number of levels of each variable, the number of cells in the design, and the number of main effects and interactions that will be relevant.

9. Explain the basic logic of three-way factorial designs.

10. Determine, from a graph, whether a study shows a three-way interaction.

11. Interpret key words that indicate factorial-design language in a journal article.

12. Interpret key words in popular media articles that indicate a factorial design.

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