Programming the statistical procedures from SAS

Mutiple within-subject factor MMRM analysis -Proc Mixed

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Mutiple within-subject factor MMRM analysis -Proc Mixed

Hi All, 

 

My name is Writwik Mandal.

 

Currently, I am working on designing a Mixed model repeated measures analysis (SAS 9.4) for a repeated measures data with three within-subject factors and one between subject factor(treatment group with 4 levels). The within subject factors are : visit (4 levels ), ear (Left, right), frequency (250 Hz,500 Hz,1000 Hz).The response variable is continuous .

 

My question is can Proc mixed "Repeated" statement be used to mention all the 3 within subject factors ? I know that two within-subject factors can be mentioned in the "repeated" statement, but i have not been able to fit three factors in one "Repeated" statement. 

Kindly guide me with syntax if any alternative way is there.How could I possible mention all three "within-subject factors" in the "Repeated " statement? I want to take a "kronecker product" of completely symmetric covariance matrix for "Ear", Unstructured cov matrix for "Frequency" and Unstructured cov matrix for "Visit".

 

I am expecting the data to look somewhat like below.


trt subj visit ear freq threshold

A 001 1 Left 250 20
A 001 1 Right 250 25
A 001 1 Left 500 30
A 001 1 Right 500 35
A 001 2 Left 250 15
A 001 2 Right 500 35
.
.
.

 

Kindly guide me with this.

 

Thanks and best regards,

 

Writwik

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