This paper is proposing a statistical method, useful for analyzing phenomena whose equations are impossible to be solved analytically. The input data consist in a collection of tabled functions, (numerically determined), named further database. Least square method based algorithms, presented in the first part of the paper, and is applied to this database. First, a trigonometric regression algorithm will find the approximating Fourier coefficients. Finally a multiple regression algorithm to fit trigonometric type function (sill, cos) is introduced. Its input data may be the Fourier coefficients, the Fourier analysis results, or whatever collection of experimental data corresponding to a set of variables. The final part of the paper is dedicated to an example, Illustrative for these.