## What is Variable:

**Variable** It is an adjective that means that something or someone varies or can vary. It also means ‘unstable’, ‘changeable’ and ‘unsteady’.

In **math** A variable is a magnitude that can have any value among those included in a set.

It comes from the Latin *variabĭlis*.

## Dependent and independent variable

Depending on the relationship of influence of one variable over another, a distinction is made between a dependent and an independent variable.

A**dependent variable** 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 symbol ‘y’.

A**independent variable** is a variable whose value is not determined by another variable. These are variables that may or may not influence or be associated with the dependent variable. In a function it is usually represented on the abscissa y axis with the symbol ‘x’.

## Quantitative and qualitative variable

A **quantitative variable** is a variable that can be expressed by a numerical value, which allows you to perform arithmetic operations on it. **examples**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** is a variable that does not correspond to a numeric value. **examples** of qualitative variables are gender, place of birth and profession.

## discrete variable

A **discrete variable** is a kind of **quantitative variable** what **cannot present intermediate values** within a set. For example, the number of existing 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 the specific values.