PSYCH291 Lecture Notes - Internal Validity, Random Assignment
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*local history some external event other than the x (or not x) that occurs in one group. History vs. local history and not the other sample. *so, by definition, history is some external event that occurs to most people in the. *local history is something that occurs to one group of people in sample. Various patterns of results one could obtain in this true expt. *various patterns of results one could obtain in a true expt. *we"ll focus on this case when researcher obtained the effect he/she predicted. Imaginary study 1: wood & i. madeitup, 2010b. X = 4-week treatment involving novel, exciting activities. To illustrate how true expts rule out threats to internal validity. *use example from research by aron et al. *how a true expt would rule out these threats. *creates conditions that are equal before the manipulation. *variables that are known to be relevant to the research. *variables that are not known to be relevant.