Variable is an adjective that means that something or someone varies or can vary. It also means ‘unstable’, ‘changeable’ and ‘inconstant’.
In math A variable is a magnitude that can have any value among those included in a set.
Comes from Latin variabĭlis.
Dependent and independent variable
Depending on the relationship of influence of one variable on another, a distinction is made between dependent and independent variables.
A variable dependent is a variable whose value is determined by the value of other variables. It is the factor observed and measured in a study. In a function it is usually represented on the y coordinate axis with the ‘y’ symbol.
A variable independent is a variable whose value is not determined by another variable. These are variables that may or may not have influence or be associated with the dependent variable. In a function it is usually represented on the x-axis and with the symbol ‘x’.
Quantitative and qualitative variable
A quantitative variable It is a variable that can be expressed by a numerical value, which allows arithmetic operations to be performed with it. Examples of Quantitative variables are a person’s weight, age and number of children.
Quantitative variables may or may not be grouped. They can also be discrete or continuous.
A qualitative variable It is a variable that does not correspond to a numerical value. Examples Qualitative variables are gender, place of birth and profession.
Discrete variable
A discrete variable is a type of quantitative variable that cannot present intermediate values within a set. For example, the number of televisions in a home (0, 1, 2, 3…).
Unlike a continuous variable, in the discrete variable there are defined values, while in the continuous variable it can take any value between two numbers.
Random variable
A random variable is a function that associates each element of a sample space with a real number. This concept is used in statistical studies.
Four types of random variables can be distinguished: discrete, continuous, binomial and normal.
It is usually represented with symbols in upper case (for example: ‘X’ and ‘Y’) and in lower case to indicate specific values.
See also: Statistics, Frequency