PSYB01H3 Chapter Notes - Chapter 8: Repeated Measures Design, Random Assignment, Internal Validity
Document Summary
The experimental method is a vital and versatile tool in a researchers toolbox. Critical advantage of the experimental method over non-experimental is that researchers can relatively unambiguously interpret results in terms of causality. Manipulates independent variable to create groups that differ in the level of that variable and then compares the groups in terms of scores of dependent variable. Confounding variables vary along with the independent variable, occurs when the effects of the independent variable and uncontrolled variable are intertwined so that you cannot determine which of the variables is responsible for the effect. Good experimental design allow researchers to make causal claims because competing alternative explanations are eliminated. High internal validity: only the independent variable can be the cause of the results. Simplest possible experimental design has two variables: independent and dependent. Researchers must make every effort to ensure that only difference between the two groups is the manipulated variable.
