Statistics How To

Continuous Variable Definition (Continuous Data)

Probability and Statistics > Basic Statistics > Continuous Variable / Continuous Data


What is a Continuous Variable?

A variable is a quantity that has a changing value; the value can vary from one example to the next. A continuous variable is a variable that has an infinite number of possible values. In other words, any value is possible for the variable.

A continuous variable is the opposite of a discrete variable, which can only take on a certain number of values.

A continuous variable doesn’t have to have every possible number (like -infinity to +infinity), it can also be continuous between two numbers, like 1 and 2. For example, discrete variables could be 1,2 while the continuous variables could be 1,2 and everything in between: 1.00, 1.01, 1.001, 1.0001…

What is a Continuous Variable? Examples of Continuous Data

A few examples of continuous variables / data:

  • Time it takes a computer to complete a task. You might think you can count it, but time is often rounded up to convenient intervals, like seconds or milliseconds. Time is actually a continuum: it could take 1.3 seconds or it could take 1.333333333333333… seconds.
  • A person’s weight. Someone could weigh 180 pounds, they could weigh 180.10 pounds or they could weigh 180.1110 pounds. The number of possibilities for weight are limitless.
  • Income. You might think that income is countable (because it’s in dollars) but who is to say someone can’t have an income of a billion dollars a year? Two billion? Fifty nine trillion? And so on…
  • Age. So, you’re 25 years-old. Are you sure? How about 25 years, 19 days and a millisecond or two? Like time, age can take on an infinite number of possibilities and so it’s a continuous variable.
  • The price of gas. Sure, it might be $4 a gallon. But one time in recent history it was 99 cents. And give inflation a few years it will be $99. not to mention the gas stations always like to use fractions (i.e. gas is rarely $4.47 a gallon, you’ll see in the small print it’s actually $4.47 9/10ths
What is a Continuous Variable?

Heights and weights are both examples of quantities that are continuous variables.

Next: Discrete vs continuous variables.




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