Hello,
I am new to Proc GLM and would appreciate help answering the following question.
I have fitted an ANCOVA model with covariate X (continuous) and two factors A and B (each with two Levels). The relationship between Y (the continuous response variable) and X is not linear therefore I have included a quadratic term for X in the model and included the interaction term x*A*B in the model as well.
The type III F-test is significant for Factor A but not significant for factor B. The interaction term X*A*B is statistically significant and x and x2 are also significant.
The LSMEANS test for Factor A is not significant while it is significant for factor B ( the opposite of Type III F-test).
Why is this?
Show us the output from your PROC GLM. Use the "Insert Photos" icon to include a screen capture of your output in your reply — do not attach files.
Interpreting higher-order interactions can be a challenge if you have not included the lower-order interactions. Have you also included the second-order interactions x*A, x*B, and A*B? Show use your GLM code.
Here it is
Thanks.
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