I have three predictor variables: one is measured, two were manipulated (2x2). The dependent variable is measured.
My main hypothesis is that the continuous predictor would lower the effect of the interaction of the manipulated predictors on the dependent variable.
Should I use hierarchical linear regression? In Step 1, I would add all predictors. In Step 2 I would add the interaction of the manipulated predictors. And in Step 3, the interaction of all three predictors. Or should I use ANCOVA?