Variable (1 of 2)
A variable is any measured characteristic or attribute that differs for
different subjects. For example, if the weight of 30 subjects were measured,
then weight would be a variable.
Quantitative and Qualitative
Variables can be quantitative or qualitative. (Qualitative
variables are sometimes called "categorical variables.") Quantitative
variables are measured on an ordinal,
scale; qualitative variables are measured on a
scale. If five-year old subjects
were asked to name their favorite color, then the variable would be
qualitative. If the time it took them to respond were measured, then
the variable would be quantitative.
Independent and Dependent
When an experiment is conducted, some variables are manipulated by
the experimenter and others are measured from the subjects. The
former variables are called "independent variables" or "factors"
whereas the latter are called "dependent variables" or "dependent measures."