Z metodologii badań nad wpływem dochodu na dzietność rodzin

Abstract

Population of families subjected to the all-Polish budgetary studies was divided into sub-populations according to the level of education obtained by the household head, duration of marriage and a character of inhabited locality. On the ground's of the regression analysis, the thesis was formulated that there is a relation between income and a number of children in a family which is adopting a form of multinomial third degree function. On the base of the differential calculus of those functions their extremes were established and the following conclusions were thus formulated. In sub-populations of divergent socio-demographic traits, the local minimam and maximam of the number of children are reaching various values. The ares of income changebility determining maxima of children number, in case of the families with the degree is on a much higher level in comparison with the remaining families. Areas of children number changebility in families with a degree or secondary education are more or less on the same level, yet it remains higher in relation to the corresponding changebilities in families with primary or vocational education. In course of prolongation of marriage lasting the maxima of children number are reaching higher values and they are defined by higher and higher level of income changebility, the upper limit value for the minima of children number is also increasing. Taking the inhabiting location under consideration it was noticed that the maxima and the upper limits of minima of the children number are the highest for the rural families and lower and lower in families inhabiting small towns, medium and large cities.