Psych 325 1st Edition Lecture 14-Finish Chapter 5: Common Threats to ValidityoRecap Part 2: Validity Threats: people changeoPart 3: The process of studying people changes people-Brief Exam 2 Review session-Regression to the Mean-Hawthorne Effect: when you're in an environment where a supervisor or leader is watching your performance automatically improves-Mere Measurement Effect: you change your behavior simply because you were asked tooBlood pressure may improve just because you participate in a studyoPeople become less depressed simply by volunteering for studies-Just knowing you are in a study can change you-Testing EffectoOn most tests,, you'll improve if you take it a second timeoWhy-Practice-LearningoWhy is this a problem?oWhat is the solution? -Attitude polarizationoIf you watch CNN or Fox or any news shows you should be familiar with thisoPeople disagree a lot about controversial topics (like abortion)-As we keep asking you about your opinions toward abortion your answers will become more extreme Intervention-->Test-->TestNo Intervention-->Test-->TestImprovement masquerades the effect -Experimental Mortality/AttritionoPeople may leave your study or fail to return for follow-upoWhen is this a problem for external validity?oWhen is this a problem for internal validity?oWhat is the solution?-Longitudinal study: study over a long period of timeoCould be within a number of a day or a few weeks or monthsoWhen people are studied over a long period of time they have more of a likelihood of dropping out of the study-Why?People are lazy, worn out, tired, malicious people, move away, oExperimental Mortality/Attrition example:-Study over 24 weeksThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.Recruit 100 people for fitness assessmentYou think your exercise intervention is going to improve people's fitness who are "unfit"Pre-test-->treatment-->Post-testMeasure fitness on a 0-10 scale (100 people)-->exercise intervention-->Measure fitness on same scale (50 people)This is homogeneous attrition because in the control group the same amount of people drop out-Heterogeneous attritionAfter post-test N=15 but in control group after post-test N=90oYou want to do everything you can to reduce attrition-Do everything you can to keep participants
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