Based on the solution of the quantum Boltzmann equation, in the linear transport approximation for an isotropic low-dimensional system, the thermoelectric power coefficient, Q, in a quantum well structure was determined. These calculations are based on variational methods, taking into account especial functions which include important parameters being varied at the time of evaluating the thermoelectric power, e.g. height and width barrier. Values of Q are carried out by using a computer code written in Mathematica, which allows one to depict them easily and in this way to compare different behaviors of Q against temperature according to the scattering mechanism (phonons).