Hi, I was looking for help with SAS IML and found the group SAS-L.

I have unbalanced repeated observations data. Say for example, n1 measurements for one subject, n2 measurements for a different subject and so on. Two covariates X1 X2 are measured on each subject, which is a matrix of the dimension equal to the corresponding number of repeated observations on each subject by 2.

Part of my data is:

ID Wgt X1 X2 1 45 7 0.5 1 47 5 0.3 1 47.5 5 0.3 1 47 7 0.6 2 53 8 0.6 2 50 8 0.7 2 51 9 0.8 3 46 10 1 3 46 8 0.9 3 49 9 1 3 51 11 1.1 3 51.5 11 1.2

I want to perform the matrix multiplication of X'XY where X is a matrix with two columns X1, X2 and Y the Wgt response vector, of one ID. I want to perform this multiplication and sum over all the IDs.

Can I get some help....

Thanks, L Hoopes