Diễn giải kết quả two-way ANOVA [trang 278]

Inference for the two-way ANOVA table involves first checking the interaction p-value to see if we can reject the null hypothesis that the additive model is sufficient.

If that p-value is smaller than α then the adequacy of the additive model can be rejected, and you should conclude that both factors affect the outcome, and that the effect of changes in one factor depends on the level of the other factor, i.e., there is an interaction between the explanatory variables.

If the interaction p-value is larger than α, then you can conclude that the additive model is adequate, and you should re-run the analysis without an interaction term, and then interpret each of the p-values as in one-way ANOVA, realizing that the effects of changes in one factor are the same at every fixed level of the other factor.