Hi Ahmad,
This issue hasbeen discussed a lot and I'm afraid there's no consensus yet.
To your question:
1. Is there away to solve this problem for the indicated formulas?
As you said, thisproblem occurs at the early/later time points. In other words,
it happenswhen prediction is relati
I also like this version:
W = SDL-(SDL-SDH)*TY/(SD50+TY)
Y=LTY+W*EPS(1)
Here SDL is the standard deviation (in logs) at low concentrations, SDH is
the standard deviation at high concentrations, TY is the individual
prediction, LTY is LOG(TY). SIGMA should be fixed at 1
Leonid
On Wed, Jun 1
Dear Ahmad,
You don't havet o choose between normal or transformed concentrations in your
error model, you can let NONMEM estimate the most appropriate transformation
for you. Combining this with a power transform error model I think is likely to
solve your problem. See
A strategy for residual
