I am analysing some data using a two-way ANOVA followed by Sidak's multiple comparisons post hoc tests. I am looking at the effect of age and genotype (the independent variables) on the levels of a certain protein (the dependent variable) expressed in the brain of mice.
After performing the two-way ANOVA, the interaction effect is statistically significant (p-value = 0.0254), but neither of the main effects are statistically significant (p-value > 0.05).
I am new to two-way ANOVA analysis and I have learnt about it from online tutorials. In the examples on the tutorials, I have seen cases where the interaction effect is statistically significant, along with one main effect.
I am wondering if it is common for result of two-way ANOVA to have only the interaction effect be statistically significant? Further, would the correct interpretation of my results be that neither age or genotype alone has a significant impact on the levels of the protein; however the age and genotype in combination does have a significant impact on the levels of the protein?
Any insights are appreciated.