ABSTRACT
A variable is a trait or characteristic that can vary within a population. Research includes different types of variables that are generally grouped into categorical variables and continuous variables. Categorical variables have mutually exclusive categories. There are two types. These are: nominal variables; and exhaustive variables. There are two types of continuous variables. These are: interval variable; and scaled variables. Interval variables have a numeric value, so they can be measured along a continuum with clearly defined intervals between values. Just like interval variables, ratio variables are numerical and can be measured along a continuous number line. A common instance in the research of reducing a continuous variable to a categorical one is age. In nonexperimental studies, some researchers refer to any variable that comes first as independent and to the one that comes later as dependent.
