Terminology

• [True] Experiment

  A study that attempts to show that changes in one variable are directly responsible for causing change in a second variable. This is accomplished through four basic elements: Manipulation, measurement, comparison, and control.
• Independent Variable

  In an experiment, the variable manipulated by the researcher. In behavioural research, the independent variable usually consists of two or more treatment conditions to which participants are exposed.
• Treatment Conditions

  The independent variable is manipulated by this. In an experiment, a situation or environment characterised by one specific value of the manipulated variable, An experiment contains two or more treatment conditions that differ according to values of the manipulated variable.
• Levels

  In an experiment, the different values of the independent variable selected to create and define the treatment conditions.
• Dependent Variable

  In an experiment, the variable that is observed for changes to assess the effect of manipulating the independent variable. In non-experiments and quasi-experiments, the dependent variable is the variable that is measured to obtain the scores within each group. It is a behaviour or response measured in each treatment condition.
• Extraneous Variable

  All variables in the study other than the independent variables.
• Third Variable Problem

  The possibility that two variables appear to be related when, in fact, they are both influenced by a third unidentified variable is controlling the two variables and is responsible for producing the observed relation.
• Directionality Problem

  Demonstrating the changes in one variable tend to be accompanied by changes in another variable simply establishes that the two variables are related. The remaining problem is to determine which variable is the cause and which is the effect.