• Two-way ANOVAs are used when we have more than one independent variable in our study.
  
  
• Two-way and more complex ANOVAs can test individual (main) effects or combined (interaction) effects.
  
  
• Interaction, or combined, effects test whether the pattern observed for one variable (e.g., year in college) differs by the second variable (e.g., male versus female).
  
  
• Always check the interaction first; we do not interpret main/individual effects if there is an interaction present in the data.
  
  
• We use multiple F ratios in two-way ANOVA. Each examines a between group effect/error.
  
  
• Effect sizes (η² or ω²) can also be calculated for two-way ANOVA.

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