This chapter is designed for the least squares method . It
begins with the least squares method to determine a polynomial
of degree n well fitted to m discrete points (xi, yi), i =
1, 2, ...,m, when n ≤ m. In the simplest form, the line of
regression through m points is determined. The algorithm
to find well fitted function to given discrete data is also
presented. The Mathematica modules are designed and example
illustrating the method are provided . The chapter
ends with a set of questions.
Keywords: The least squares method, Regressions.