Biology 2244A/B Chapter 7.1,8.1: Reading 2 - Study Designs
16 Sep 2016
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Understanding the definitions of: subjects, treatments, explanatory variables (i. e. factors), response variables, control groups, placebo. Observational study: observes individuals and measures variables of interest but does not attempt to influence the responses: purpose: describe and compare existing groups or situation, ex. What is the population of americans that are overweight. Experiment: deliberately imposes some treatment on individuals in order to observe their responses: purpose: to study whether the treatment causes a change in the response, ex. Does aspirin reduce chance of heart attack: better when our goal is to understand cause and effect. Treatment: any specific experimental condition applied to the subjects in an experiment. Confounded: two variables (explanatory or lurking variables) are said to be this when their effects on a response variable cannot be distinguished from each other: example: drinking wine/beer is confounding by dietary habits and other lifestyle factors.
