What does a two-way ANOVA assess?

• A. It examines effects of two independent variables on a dependent variable and tests for interaction between factors.
• B. It compares two mean values across one factor.
• C. It analyzes the relationship between a predictor and a binary outcome.
• D. It evaluates the reliability of measurement instruments.

Answer: (A)

Two-way ANOVA examines how two categorical factors together influence a continuous outcome, and it also tests whether the effect of one factor depends on the level of the other—that is, whether there is an interaction between the factors. For example, you might study how study method (mnemonic vs. repetition) and time of day (morning vs. evening) affect memory test scores. You’d see the overall effect of study method across times of day, the overall effect of time of day across methods, and whether one method performs differently depending on whether it’s morning or evening. This approach lets you assess both main effects and the interaction, which is what sets it apart from a simple comparison of two means or a one-factor ANOVA. It isn’t used for predicting a binary outcome (that would be logistic regression) or for assessing reliability of measures (which uses reliability analyses).