The field of Psychology prides itself on the use of empirical knowledge to discern the cause and effect relationship between phenomena. In order to achieve this, scientists utilize the experimental method. This method involves the manipulation of variables in order to determine cause and effect relationships. In doing so, there are scientists need to gather several pieces of information.
Random assignment- scientists make sure that participants have an equal opportunity to make either the control and experimental groups.
Control Group- This is the group exposed to normal condition.
Experimental group- This is the group that has its variables manipulated.
Independent variable- This refers to the variables that is being controlled
Dependent variable- This is the variable that is being measured.
This video shows these definitions in action. http://www.youtube.com/watch?v=G7bpwbnged4&feature=player_detailpage