Answered By: Steven Profit
Last Updated: Sep 15, 2015     Views: 3407

Categorical variable (as defined in the Penguin Dictionary of Mathematics):
random variable whose values are categories. For example, side effects of a drug classed as (none, slight, moderate, severe), character classifications (introvert, extravert), times to failure of a machine part (< 100 hours, 100-199 hours, 200-299 hours, ≥300 hours), and marital status (single, married, widowed, divorced). Where there is no natural ordering of the categories, the variable is described as nominal. Thus marital status is a nominal variable. If there is a natural ordering of categories, the variable is described as ordinal. Thus the side effect of a drug is an ordinal variable. Categorical variables that can take only two possible values are called dichotomous variables.

Numeric variable (as defined in the Oxford Dictionary of Psychology):
In statistics and measurement theory, any variable whose values are numbers.