Hi Everyone, I am new to the community and having trouble about writing the syntax for my specific data in SAS. This is my first time trying doing a mixed model analysis so I apologize if the question is not enough brain-storming. I have a 3-level nested hierarchical model: Consider the famous example of students (level 1) nested in classes (level 2) where the classes are nested in school (level 3). I have no covariate in level 1; covariates X and B in my level 2; and covariate sC, D, E, F in level 3. Controlling covariates B, C, D, E, F, I want to see the fixed as well as random effects of X on the response Y. I have added a sample data (in .xlsx). This is a cross-sectional study. For serving my analysis goal I think one of these two models will do (I will chose the better one based on AIC/BIC): 1. PROC MIXED data=SampleData covtest noclprint method = REML;
class level2 level3;
model Y= X B C D E F ddfm = SATTERTHWAITE;
random intercept/ sub=level3;
random intercept X/ sub=level2 (level3) type=UN;
run; 2. PROC MIXED data=SampleData covtest noclprint method = REML;
class level2 level3;
model Y= X B C D E F ddfm = SATTERTHWAITE;
random intercept X/ sub=level3 type=UN;
random intercept X/ sub=level2 (level3) type=UN;
run; For testing assumption I am reading macro for testing 2-level mulitlevel model However, my model is 3-level model, is there any resources on how to test the assumptions for 3-level model? And how badly are we impacted if those assumptions are not met?
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