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