PSYCH291 Lecture Notes - Lecture 22: Internal Validity, Random Assignment, Demand Characteristics
16 Dec 2018
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Document Summary
Quasi-experimental research (between-subjects example) results: medal type and happiness. Design feature was different than traditional experiment. Iv was measured, not manipulated because it would not be possible (or ethical) to assign medals at the olympics. results: music loudness and unhealthy eating. Design feature was different than traditional experiment Participants not randomly assigned to the two conditions. Psychologists who conduct quasi-experimental research groups often interested in comparing naturally occurring groups (e. g. comparing happiness of silver medalist vs. bronze medalist) Iv sometimes cannot be manipulated (or if it can be, random assignment isn"t possible) results in threats to internal validity that should be addressed if possible. Benefit of quasi-experimental designs is their naturalism. They have strong ecological validitybecause they study groups in the real world. Psychologists test the hypothesis that an already scheduled event (e. g. new policy) causes a change in a dv. Study: impact of delaying school start time on adolescent sleep, mood and behaviour.
