Modelowanie statystyczne zjawisk z trendem i sezonowością

In quite a considerable number of economic and natural issues, during research, observation series are obtained with a very distinct seasonal dependence and trend, whether constant or vaguely outlined. Chance variations (randomness) of this type is encountered in climatology, when it comes to describing average monthly temperatures of air and the ground, and in temporal series describing production of, not infrequently elementary, commodities. For description of these phenomena, the model has been proposed (see in text). Proposed model has been used in a description of power (electric energy) production in Poland, employing monthly empirical data from the period of 1974-1993.