use of existing data in order to test a hypothesis
observation of naturally occuring behavior without intervention
a sample of people is asked a series of questions about their behavior, thoughts, and attitudes in order to represent a target population
an in-depth intense investigation of an individual or small group of people
the relationship between two sets of variables is examined to determine whether they are associated or "correlated"
behaviors, events, or other characteristics that can change, or vary in some ways
the relationship between two (or more) variables is investigated by deliberately producing a change in one variable in a situation and observing the effects of that change on other aspects of the situation. the only way to test "cause and effect". does on variable cause a change in another variable?