L24 Math 3200 Chapter 3-4: Homework 1 Notes
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Comparative study: compare two or more alternative methods or groups. Compare the effectiveness of different management training methods. Noncomparative descriptive study: purpose is to learn about the characteristics of a group but not necessarily to make comparisons. Studies to estimate the number of illiterate americans. Rate of defective parts produced by a manufacturing process. Observational study: records data without interfering with the course of events. Do not establish causation -- can only establish associations. There is no way to know whether the observed data is caused by the predictor variable or by the confounding variable -- if the confound is not known to the observer, it is a lurking variable. Experimental study: researcher actively intervenes to control the study conditions. Sample survey -- provides snapshot of population based on a sample observed at a point in time. Prospective study -- follows a sample forward in time. Retrospective study -- follows a sample backward in time.
