THE SAMPLING

As Canavos to understand the nature of statistics it is necessary to understand the population notions —also called universe or collective (Canavos, 1988). A population is the collection of all the possible information that characterizes a phenomenon.

In statistics, population is a much more general concept that the one held by the general definition of this word. In this sense, a population is any collection, whether it is of a finite number of measurements or a big collection, virtually infinite, of data about something of interest. On the other hand, the sample is a selected representative subset of a population (Lea & Brooke, 2004; Ross, 2009). A good sample is that which reflects the essential characteristics of the population from which it was obtained. In statistics one resorts to random methods to guarantee these essential characteristics.