Five computer programs for testing weighted residuals and calculating linear confidence and prediction intervals on results from the ground-water parameter-estimation computer program MODFLOWP

Abstract

This report documents five computer programs, YR, NORM, BCINT, YCINT, and BEALEP, that use results from the ground-water flow and parameterestimation computer program MODFLOWP. MODFLOWP uses nonlinear regression to estimate parameter values. Programs YR and NORM produce data sets for two commonly used graphs of weighted residuals that are important in analyzing regression results. Programs BCINT and YCINT calculate linear confidence intervals on parameter estimates, and linear confidence and prediction intervals on simulated hydraulic heads and simulated flows along head-dependent boundaries. These intervals are essential for displaying the reliability of simulated results, and can be used to make sensitivity analyses much more accurate than is allowed by traditional methods. Program BEALEP computes a measure of model linearity, which is needed to determine the accuracy of the linear intervals calculated with programs BCINT and YCINT. This report includes a discussion of the purposes of all the programs and how results can be used, brief descriptions of the theory behind each program, illustrative examples of how the programs may be used, descriptions of program input and output, and listings of the FORTRAN source codes.