Discrete Variable Definition – What it is, Meaning and Concept

The variables are symbols that can acquire different values ​​and that appear in formulas, algorithms, functions and propositions of mathematics and statistics. According to their particularities, they are classified in different ways.

There are random variables, dependent variables, independent variables, qualitative variables, quantitative variables Y continuous variables, among other. On this occasion we will refer to the discrete variables.

It is interesting to know the etymological origin of the two words that give shape to the term that now occupies us:
-Variable derives from Latin, more exactly from “variabilis” which is the result of the sum of two elements of that language: the verb “variare”, which can be translated as “change of appearance”, and the suffix “-able”, which it is used to indicate “possibility”.
-Discrete, on the other hand, also comes from Latin. In his case, it is the result of the union of two other components: the prefix “dis-“, which is used to specify “separation”, and the verb “cernere”, which can be translated as “separate” or “sift”.

A discrete variable is one that is in a position to adopt values of a given numerical set. That is, it only acquires values ​​from a set, not just any value.

There is a distance between the potentially observable values ​​of a discrete variable that is impossible to determine. “to complete” with intermediate values. Therefore, between two values ​​there is at least one value that is not observable.

The number of cars that a person has is a discrete variable. A man you can have, for example, A car, two cars or three cars, to name a few possibilities. But it can’t have 1.6 automobiles neither 2.8 automobiles.

In a similar sense, the number of children of a woman it is also a discrete variable. They can be had two, 4 or 6 children, never 2.1 or 5.78 children.

Many others are the examples of discrete variables that can be used to understand them. Specifically, among these are the following:
-The gender of the human being, which will be female or male.
-The number of students in a class. And it is that there may be 15, 20 or 30 students, but not 15.3 or 20.8.
-The number of fouls that can be whistled by the referee in a soccer match.
-The number of radio or television channels you have at home.
-The number of workers who make up the workforce of a company.

Instead, continuous variables they can acquire any value in an interval, always existing other intermediate values ​​between two observable values. The existence of more or less values ​​depends on the precision of the measurement. For example: a child’s height can be 1.2 meters, 1.24 meters or 1,249 meters according to how it is measured. This implies that certain measurement errors are recorded.

On the contrary, with regard to continuous variables, we can make use of other examples to understand them:
-The weight of a man or a woman.
-The weight of the peaches that have been bought in the market.
-The speed that a car reaches.
-The width of a person’s waist.