Variables are symbols that can take on different values and appear in formulas, algorithms, functions, and propositions in mathematics and statistics. Depending on their characteristics, they are classified in different ways.
There are random variables, dependent variables, independent variables, qualitative variables, quantitative variables and continuous variables, among others. On this occasion we are going to refer to discrete variables.
It is interesting to know the etymological origin of the two words that form the term that now concerns us:
-Variable derives from Latin, more precisely 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 is used to indicate “possibility”.
-Discreet, on the other hand, also comes from Latin. In his case, it is the result of the union of two other components: the prefix “des-”, which is used to specify “separation”, and the verb “cernere”, which can be translated as “to separate” or “to sift”. ”.A discrete variable is one that can take values from a given numerical set. That is, it only acquires values from a set, not any value. There is a distance between the potentially observable values of a discrete variable that it is impossible to “fill” with intermediate values. Therefore, between two values there is at least one value that is not observable. The number of cars a person owns is a discrete variable. A man may have, for example, one car, two cars, or three cars, to name a few possibilities. But you can’t have 1.6 cars or 2.8 cars. In a similar sense, the number of children a woman has is also a discrete variable. You can have 2, 4 or 6 children, never 2.1 or 5.78 children. Many others are examples of discrete variables that can be used to understand them. Specifically, they include 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 can be 15, 20 or 30 students, but not 15.3 or 20.8.
-The number of fouls that the referee can call in a football match.
-The number of radio or television channels you have at home.
-The number of workers that make up the workforce of a company.
On the other hand, continuous variables can acquire any value in an interval, and there are always 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 depending on how it is measured. This implies that certain measurement errors are recorded. On the contrary, regarding continuous variables, we can use other examples to understand them:
-The weight of a man or a woman.
-The weight of the peaches bought in the market.
-The speed of a car.
-The width of a person’s waist.
