I'm trying to help several of our scientists with constructing inverse
prediction intervals for models estimated with nonlinear least squares. So
for example, we might estimate mean of y from a 4 parameter logistic
function of x [e.g., using SSfpl in nls()], but then want to estimate a
prediction interval for x estimated from y (calibration problem, inverse
prediction). I've done some searching of R archives and found the
nlscal() function in package quantchem but this only seems to provide
inverse estimates not intervals (although quantchem does have a function
for inverse prediction intervals of linear models). Is anyone aware of
another function or package in R that will provide for inverse prediciton
intervals for nonlinear least squares? I will confess that I'm not
cognizant of whether there is well developed, accessible theory for
inverse prediction intervals in the nonlinear model.
Brian
Brian S. Cade
U. S. Geological Survey
Fort Collins Science Center
2150 Centre Ave., Bldg. C
Fort Collins, CO 80526-8818
email: [EMAIL PROTECTED]
tel: 970 226-9326
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