A discrete variable is one that cannot take on all values within the limits of the variable. For example, responses to a five-point rating scale can only take on the values 1, 2, 3, 4, and 5. The variable cannot have the value 1.7. A variable such as a person's height can take on any value. Variables that can take on any value and therefore are not discrete are called continuous.

Statistics computed from discrete variables have many more possible values than the discrete variables themselves. The mean on a five-point scale could be 3.117 even though 3.117 is not possible for an individual score.