SECTION 15.2 Summary

• As with one-way ANOVA, the model assumptions should be assessed. Preliminary analysis includes examination of means, standard deviations, scatterplots, histograms, and Normal quantile plots.
• The calculations for two-way ANOVA are organized in an ANOVA table.
• statistics and -values are used to test hypotheses about the main effects and the interaction.
• Careful inspection of the means is necessary to interpret significant main effects and interactions. Plots are a useful aid.