Development of a code FITWR for nuclear cross section statistical analysis

•We used the weighted least square with nonlinear regression method to fit experimental nuclear data.•The FITWR code has been successful applied for both light and heavy nuclei with many resonance points.•More improvements will be applied in the future, by including a new methods for nuclear data fitting.

A computer program named FITWR has been developed and applied to the experimental total cross sections for MEV incident energy particles such as neutron and proton. The computer program FITWR adapted the weighted least square method with weighted mathematical models with nonlinear regression applied to high order fitting polynomial, in order to meet the growing demands of the experimental nuclear data. The computer program FITWR deals with variance and covariance data provided along with experimental data and yields those for the evaluated ones.