Hi I performed a regression analysis on a model nonlinear in parameters. The function is: q = ( k* P^n ) + (k2 * P2^n2) where P and P2 are independent variables, k, n, k2, n2 are parameters. The estimates and their variances can be obtained, as well as correlation between any two parameters. The question is: how do I estimate the standard error in the first term of the equation? That is, what is the error in estimating w = k* P^n? Notes: The estimated standard error in q turns out to be small. But variances in parameter estimates are large. The correlations are very high, close to -1. Thanks in advance. Jiwu Rao [EMAIL PROTECTED] ================================================================= Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =================================================================