PSYB01H3 Chapter 8: PSYB01 Chapter 8
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Researcher manipulates the independent variable, to create groups that differ in levels of variable then compares groups in terms of their scores on dependent variable . All other variables are kept constant through: (1) direct experimental control (2) randomization. Cofounding variable: variable that varies along with independent variable . Occurs when effects of independent variable and uncontrolled variable are intertwined. Cannot determine which of the variable is responsible for observed effect . Would not be a factor if the variable is held constant in both conditions . Good experimental design = eliminate possible confounding that results in alternative explanation . Internal validity: when results of experiment confidently attributed to effect of independent variable . Must conduct experiment that only independent variable can be cause of results . Independent groups design: (also called between-subjects design ), different participants are assigned to each level of the independent variable using random assignment.