two way ANCOVA post hoc test multi comparisons.

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VS
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two way ANCOVA post hoc test multi comparisons.

VS
Hi,

I have the following data set:
- Dependent variable (DV)
- Continuous covariate (CO)
- Factor  A (2 levels)
- Factor B (2 levels)
After testing for the required assumptions, I am using the following commands to run an ANCOVA:

mod = aov(DV ~ CO *A*B, data)
Anova(mod, type="III")

I have 2 questions:
1) What kind of post doc multi comparisons I have to use if I don’t detect interaction of factor A and B with CO?

2) What kind of post doc multi comparisons I have to use if I detect interaction of factor A and B with CO?

I read a lot of things that did not answer properly to these two questions.
Cold you help me?