CRMJ 368 Study Guide - Final Guide: Internal Validity, Statistical Process Control, Time Series
3 Jun 2019
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Document Summary
3 elements: (1) independent and dependent variables (2) experimental and control groups (3) pretesting and posttesting (except for posttest-only design) Characterized by random assignment to experimental and control groups. Intended to rule out certain threats to internal validity: (1) selection bias, (2) history (3) maturation (4) attrition (5) testing effect and only the independent variable will differ between experimental and control conditions! Classic experimental: random assignment of subjects to experimental & control groups, preliminary measurement of dv before treatment (check of random assignment, introduction of iv (treatment) in experimental condition, measurement of dv after iv (treatment) is introduced. Still potentially vulnerable to the testing effect threat to internal validity. Useful for comparing the effects of different treatments, or different amounts of a single treatment. There will be one control group but multiple experimental groups. O2: random assignment of subjects to experimental and control groups, introduction of iv (treatment) in experimental condition, measurement of dv after iv (treatment) is introduced.
