The statistical population it is a random variable related to the objects or individuals that one intends to study in an investigation. Each of the elements of the population is called an individual and they share some characteristics.
A statistical population can be a group of really existing objects / people (for example, the set of all the people of a town) or a hypothetical and potentially infinite group of objects conceived as a generalization (for example, the set of all the plays possible in chess).
When the number of individuals in the population is large and a study is wanted, the population is divided into samples , which are small groups that have characteristics similar to the general population.
Generally, the adjective of target population is added, because it is the population on which you want to obtain a concrete result.
It is important that this population is defined in terms of time (a specific period of time: years, months, days, hours, minutes, etc.), and space (a continent, a country, a neighborhood, etc).
In statistics, that sample must be representative of the population from which it is extracted. In this way, the results obtained with this can be extrapolated to the rest of the population by statistical inference.
The qualities that describe this population for research purposes are called statistical variables and can be qualitative or quantitative.
On the other hand, there is the term population of observations, referred to the set of values that can have a statistical variable in the target population. This means that a single population can have many populations of observations.
The 8 main types of the statistical population
According to the number of individuals that make up the statistical population, these could be classified into:
1- Finite population
It refers to groups of individuals in a clearly defined amount, such as the inhabitants of a city, balloons in a pool, boxes in a warehouse, among others. They can be counted and grouped.
Some examples of this type of population would be:
- Number of students in a university.
- Number of cars sold during 2017.
- Earthquakes of magnitude greater than 4 ° on the Ritcher scale occurred in a city.
2- Infinite population
These are incommensurable populations. However, it is a purely conceptual notion, given that every population is composed of objects or individuals in finite quantities.
Among the cases of infinite population could be mentioned as examples:
- The grains of sand on a beach
- The amount of waves that break against a reef in a day.
- The drops of water that fall during a rain.
3- Real population
It is the group of concrete elements, such as: the number of people of productive age in Latin America .
Other examples could be:
- The number of users of a certain mobile application.
- The number of civil protests in a city for a month.
- The chapters of a television series.
As you can see, these examples are, at the same time, those of a real and finite population.
4- Hypothetical population
It is a concept that applies when one is working with possible hypothetical situations. For example, how many people could survive a catastrophe?
It is related to the population of hypothetical observations that occurs when you are working with samples of observations referring to psychological concepts such as anxiety , fear, etc.
In this case, the population of observations is hypothetical, potential.
Example of this would be:
- The level of anxiety that drug addicts would have to voluntarily follow a specific treatment.
- The level of fear that people can feel when going through a specific experience.
- The anguish that a mother can feel when losing her son in an amusement park.
5- Stable population
It is called this way to the groups of elements that maintain their qualities almost intact for a long period.
Some examples of these cases have to do, for example, with:
- Changes in the geology of a territory
- Movement speed of the stars
6- Unstable population
The qualities of this type of population vary constantly.
7- Dependent population
It is the type of population that changes its values for a definite reason, an identified cause. The dependence can be total or partial.
An example of this could be:
- The level of sales of a product that may depend on: product quality, advertising, distribution, etc.
8- Polynomial population
There is talk of a polynomial population when there is interest in research about several of its characteristics.
For example: a population census, in general, collects information on different variables of the inhabitants (age, location, level of income and education, etc).
References
- School (s / f). Population and statistical sample. Recovered from: escuelas.net
- García, José (2002). Statistics. Statistical Program of the ISEI, CP. Retrieved from: colposfesz.galeon.com
- Complutense University of Madrid (s / f). Definition of population. Retrieved from: e-stadistica.bio.ucm.es
- University of Buenos Aires (s / f). Glossary of statistical concepts. Retrieved from: psi.uba.ar
- Universe formulas (s / f). Statistical population. Retrieved from: universoformulas.com
- Wikipedia (s / f). Statistical population. Retrieved from: en.wikipedia.org