Programming the statistical procedures from SAS

Mixed model, random effects vs. random intercept model

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Mixed model, random effects vs. random intercept model

Hi All

 

Happy Friday!!

 

So I am trying to fit a mixed model in sas but I am not sure which model will be best suited in my situtaion. Your help is greatly appreciated.

 

Experiment: Our examiners took measurements on lumbar spine at landmarks L1-- L5. So we are doing a comparison of baseline to final. 2 diffrent labs, 8 students in each lab palpated 1 subject each time.Total 6 labs. 2 at baseline and 4 at final. A group of 8 examiners take measuement on spine at 5 locations on L and R side. In baseline we had 2 subjects whose backs were palpated, and in final we had 4 subjects whose backs were palpated. My outcome is continuous. In final lab, 4 diffrent subjects were palpated and one grp of 8 examiners palpated first two subjects only and other grp palpated other 2 subjects at a later time.

 

PROC glimmix DATA=DAT NOITPRINT ;
CLASS SUBJECT AE  LUMBAR side;
MODEL EDIST = lumbar|side;
RANDOM SUBJECT ae(subject) ;
lsmeans lumbar*side/plot=meanplot(sliceby = side join cl);run;

Running this model I see that only lumbar seems to be sigificant. But anyways I kinds knew that, I want to estimates the distance for each subject , so I can see if  distances are diffrent for baseline and final. I am not sure of the best way to do that.

 

I also tried the random intercept model for each subject and examiner interaction, but again I am not sure how do I see the diffrence in baseline and final. I am confused between random intercept model and random effects model , which is best for my case.

 

Thank you so much for your time!!

 

 

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