Probability distributions of number of births and their applications.

This paper develops probability distributions to describe the variations in the number of live birth-conceptions to a female during a given time interval (0, To) of length To. In the derivation, the interval (0, To) is divided into 2 consecutive segments, and fertility parameters within each segment are assumed to be constant but may differ between the segments. A method of obtaining maximum likelihood estimates of the parameters is outlined. The models are applied to an observed set of data. An application of the models in the evaluation of family planning programs is illustrated.