search for: paird

Hi Im attempting to build a sample variogram for 300 obersvations of longitudinal data. So what I need to do is compute the half squared differences between pairs of residuals (for instance if a subject has 4 obersvations, this is 4 choose 2 paird differences) for each subject. Also, then I need the corresponding time differences within each individual. So the end result will be a 300 by 2 matrix with columns corresponding to paired difference residuals within subject and time differences within subject. Basically im having trouble coding th...