PSYB01H3 Chapter Notes - Chapter 8: Repeated Measures Design, Confounding, Random Assignment
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Variables are kept constant by either experimental control or by randomization. Confounding variable- variable that varies along with the independent variable: effects of the independent variable and an uncontrollable variable are intertwined so you can"t determine which of the variables is responsible for the observed effect. Internal validity- ability to draw conclusions about causal relationships from our data. 2 equivalent groups of ps are used: to avoid selection differences- people selected to be in the conditions can"t differ in any systematic way, randomization or having same p do both conditions. Introduce the independent variable: experimental group gets the treatment, control group doesn"t. Measure the effect of the independent variable on the dependent variable: same measurement is used for both groups, statistically significant test can be used. In this test, the pretest is given before the experimental manipulation is given. Makes sure that the groups were equal in the beginning of the experiment.
