PSYC 221 Lecture 2: Lecture 2
23 Jan 2019
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Jan 10: correlations- two variables change together, goal: predict one variable based on another, experimental methods, goal: infer that changes in one variable cause changes in another. Hypothesis: science centers around idea of testing hypothesis, a testable explanation of a phenomenon, must be specific enough to shown to be wrong. Causal direction: a correlation doesn"t tell you the direction of causation, what caused what, could be a third variable affecting both. In correlation, a third variable caused both changes: possible neither variable studied directly affects each other. Inferring causality: experiments involve random assignment, correlations do not, why randomize, a way of distributing the other variables, equally distributed variables, only changes are due to directly studied/manipulated variables. Independent variable: what the experimenter manipulates, dependent variable, what the experimenter measures, value depends on independent variable. Confounding variable: a variable that correlates with the independent variable, assumption: keeping everything equal between the groups limits confounding variables.
