The variables in a study can also be described in terms of the types of values that can be assigned to them. A **discrete variable** consists of separate categories that cannot be divided. Take the variable *gender* for example. Generally, you are either male or female—the categories are indivisible. Discrete variables usually define categories or are restricted to whole, countable numbers. The variable *felony convictions *is an example. Either you have been convicted of no felonies, or you have been convicted of a whole number of felonies. You cannot have been convicted of 2.78 felonies. Another common way to look at discrete variables is as counts of things.

A **continuous variable**, on the other hand, can be subdivided into an infinite (or practically infinite) number of fractional parts. *Annual household income* (measured in dollars and cents) is a good example of a continuous variable. Variables that are continuous can be imagined to be along a line (like the number line) with no obvious points of separation. Note that it will be rare for any two subjects to have the same exact score on a continuous variable.

### Key Terms

**Variable, Constant, Continuous, Discrete, Experimental Group, Control Group, Independent Variable, Dependent Variable, Environmental Variable, Data, Attribute (of a Variable), Level (of a Variable)**

Last Modified: 06/29/2018