After reading this chapter, you should be able to do the following:

• Explain when to use a two-factor analysis of variance (ANOVA)
• Describe the three F ratios generated by a two-factor ANOVA
• Write null and research hypotheses for the main effects and interaction F tests
• Identify which means are compared when computing each main effect and interaction F tests
• Complete an ANOVA summary table
• Define the critical region for each F test
• Determine whether you should reject each null hypothesis
• Compute effect sizes for each main effect and the interaction, and describe each as small, medium, or large
• Use SPSS to perform a two-factor ANOVA and create a graph of the main effects and interaction
• Use SPSS to compute simple effect analyses
• Summarize the results of the ANOVA using American Psychological Association (APA) style
• Interpret the SPSS output for a two-factor ANOVA