Variable

A characteristic or property that can take on different values.

Constant

A characteristic or property that can take on only one value.

Discrete Variable

A variable that consists of isolated numbers separated by gaps.

Continuous Variable

A variable that consists of numbers whose values, at least in theory, have no restrictions.

Approximate Numbers

Numbers that are rounded off, as is always the case with values for continuous variables

Experiment

A study in which the investigator decides who receives the special treatment.

Independent Variable

The treatment manipulated by the investigator in an experiment

Dependent Variable

A variable that is believed to have been influenced by the independent variable.

Observational Study

A study that focuses on detecting relationships between variables not manipulated by the investigator.

Confounding variable

An uncontrolled variable that compromises the interpretation of a study.