05-30-2012 01:06 PM
Using proc mixed to analyze price prediction data and seeking some assistance in the repeated clause.
specifies the defining variable of the (in my case CS) matrices
we are interested in the effect of thr group statement... it is our understanding that in a situation where the group statement defines a between subject variable such as
group = gender
both male and female subjects would now be allotted their own R
the issue is that we are also interested in group on a within subject effect (lets say trials) and are looking to evaluate matrices within the subject matrix
As all of a single respondent's answers are related wedo not want 0's assumed in the off diagonals within the ID matrix
My co-authors and I are considering something of the following
group = subjectid*trials
group = trials(subjectid)
Anyone out there familiar with this problem/aware of a solution?
05-31-2012 07:58 AM
You are definitely on the right track. The last two group= statements are equivalent, when it comes to constructing the R matrix. It will be block diagonal, with each block being a CS submatrix referring to the subject-trial combination. I am curious about the full design--it may be that a doubly repeated measures using type=UN@CS might be an approach to consider. However, the best specification is all dependent on the design. More info would probably clear this up pretty quickly.
06-01-2012 08:51 AM
Overnight I thought of something. Does the variable trials index repeated observations? If so, then perhaps it is as simple as changing the type= from CS to CSH. Still, more information on the design would make this much easier.