Theory - [T13]

Population

In statistics a population can be seen as a collection of single data points (statistical units), and it represents the object of a statistical analysis. To make a simple example a population could be a class of students, each student represents a statistical unit. The aforementioned example is very simple and takes into consideration a relatively small population, since the number of students in a class are not so many. This makes it easy to treat the entire population as the object of our statistical study, as in the case of Descriptive Statistics, therefore in this instance we can conclude that the dataset used for the statistical analysis is the same as our target population. On the other hand we have the case of Inferential Statistics, in which the population is just theoretical, since it is too large to collect factual data for every element of the it. Therefore we conduct our analytical study onto a smaller subset: a Sample, which we deem to be a good representative of our larger population.

Sampling Distribution

A Sampling Distribution is a function derived from a dataset, and it shows both in a mathematical and visual way, all the possible values a variable can take as well as how often they occur. A distribution is a powerful tool that allows meaningful conclusion to be drawn in a statistical analysis. It is particularly useful in inferential statistics, where it puts in evidence crucial information about the population target of our study.