ABSTRACT
The mean of the probability distribution of the number of male births corresponds to the mean number of male births born in all the hospitals, that is, the total number of male births divided by the number of hospitals. From birth to death, the consequences of our actions are governed by probabilities. Defining probability may appear easy but in reality is very difficult. As the notion of probability applies only to situations where there is uncertainty, these are such that there is always more than one possible outcome. A simple example consists of throwing a six-sided die. The die must be bona fide, that is, it must be perfectly symmetrical and homogeneous.
