Psychology 1000 Lecture Notes - Lecture 4: Observer-Expectancy Effect, Internal Validity, Random Assignment

• School: Western University
• Department: Psychology
• Course: Psychology 1000
• Professor: Mark Holden

Document Summary

One (or more) variables is manipulated to determine if it influences other variables: manipulation makes this the only method that allows for conclusions about causes. Independent variable: any variable that is manipulated by the experimenter. Dependant variable: the variable that is measured to see if the iv influences it (the outcome) Control things that can affect the dv other than the iv: confounding variable (extraneous variable): a controlled variable that may affect the result of the experiment apart from the iv. Experimental vs. control groups: most experiments have an experimental and a control condition. There may be multiple levels of the experimental condition. Different groups of participants are assigned to each level of the independent variable and then the dependant variable is measured for participants in each group: e. g. 50% to the control group, 50% to the experimental group. Solution: random assignment (flip a coin to see who goes into what condition)