How many hypotheses are typically tested in a two-way ANOVA?

In a two-way ANOVA, researchers typically test three hypotheses. These consist of two main effects and one interaction effect. The main effects are the individual effects of each independent variable on the dependent variable, while the interaction effect assesses whether the effect of one independent variable on the dependent variable differs depending on the level of the other independent variable.

For instance, if you are examining the effects of two different teaching methods and two different age groups on test scores, the main effects would look at how teaching methods and age groups independently influence scores. The interaction effect would evaluate whether the impact of a teaching method varies at different age levels.

This approach allows for a more nuanced understanding of data by considering how multiple factors work together rather than isolating each factor individually. Thus, understanding that three hypotheses are tested in a two-way ANOVA is essential for correctly interpreting the results of this statistical analysis method.