Biology 2244A/B Chapter Notes - Chapter 7: Longitudinal Study, Simple Random Sample, Dependent And Independent Variables
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Biology 2244a topic 1 sampling and study design. The practice of statistics in the life sciences. Observational study: where subjects are disturbed as little as possible when gathering data. Observes individuals and measures variables, but doesn"t influence response. Experiment: imposes treatment/condition on individuals in order to observe responses. Purpose = to study whether treatment changes response. Observational study is a poor way of gauging effect of intervention: cannot prove conclusion variables are confounded. Explanatory variable: explains/influences changes in another variable, also called independent variable. Response variable: measures outcome of study, also called dependent variable. Lurking variable: not among explanatory and response variables of the study, yet may influence the relationships among them. Explanatory and lurking variables are confounded when their effects on response variable cannot be discriminated. Individual: object described by a set of data. Population: entire group of individuals in statistical study about which we want information. Sample: part of population from which we actually collect information.