Good day, all. I'm back to the trough.
I have created a model of blood pressure over time as a function of assigned
treatment. With the model I can get estimates for the blood pressure by time
and group using predict.lme(). But unlike other predict()s, predict.lme()
doesn't accept the parameter se.fit=T. Of course, I can extract the vector of
coefficients and the cov matrix from the model and do the required matrix
arithmatic. But it is sort of tedious to build the design matrix for the
various combinations of treatment, time, and the interactions.
Am I missing a simpler way to do this, using an extraction function that I have
missed?
Alternatively (or additionally), is there an easy way to build a design matrix
for TRT*VISIT?
As always, many thanks in advance to any of you that can help me.
Larry Hunsicker
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