Statistics: Basic Concepts: Variables

Lesson 3: Variables


What are variables?

Variables are characteristics or qualities of a person, animal, or object that you can count or measure. As the term suggests, the value of the variable can vary, or change. For example, a person’s age, a dog’s weight, or the height of a building are all different types of variables.

Watch the following video to learn more:

Types of variables

There are two types of variables that are used to analyze and interpret data: qualitative variables, and quantitative ones. 

  • Qualitative variables are characteristics of an individual or object which can only be expressed in words. Some examples include ethnicity, profession, or gender. 

  • Quantitative variables are characteristics that can be expressed in numbers. For example, weight, height, and length can all be written numerically. 

In turn, quantitative variables are divided into discrete and continuous ones.

  • Discrete variables can only have a specific set of values that cannot be divided into smaller parts. For example, if you were counting students in each class and had numbers like 23, 22, 14, and 28, you couldn’t include a number like 27.8, because students cannot be subdivided! Generally, discrete variables do not include decimals. 
  • Continuous variables are those that can take any value between two numbers. For example, if you need to write the height of a group of basketball players in meters, you could include values like 1.78, 1.65, 1.45, because height can be expressed in that way. You could also use continuous variables to measure things like temperature or the distance between two points. 

In the next lesson, we’ll teach you how to create a frequency table