Psychology 2840F/G Chapter 11: research methods tb 11
3 Oct 2018
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Research methods textbook notes chapter 11 confounding and obscuring variables. Potential internal validity threats in one group, pretest/posttest designs: (1) maturation. A change in behaviour that emerges more or less spontaneously over time. Spontaneous remission is another name for maturation: (2) history. Some threats occur not just because time has passed but because something speci c has happened between the pretest and post-test. To be a historical threat the external factor must affect everyone or almost everyone in the group: (3) regression. Refers to a statistical concept called regression to the mean: e. g. when a performance is extreme at time 1, the next time that performance is measured (time 2) it is likely to be less extreme. Only occur in a pretest/post test design and only when a group has an extreme score at pretest: (4) attrition. Can happen when a pretest and post-test are administered on separate days, and participants are not available on the second day.
