Statistical Sciences 2244A/B Chapter Notes - Chapter 7-8: Simple Random Sample, Recall Bias, Observational Study
13 Sep 2016
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Observational study: observes variables but do not influence responses. Experiment: imposes treatment on individuals to observe responses. Confounding: two variable"s effects cannot be distinguished from each other. Population: study of the entire group of individuals. Sample: a part of the populations that we actually collect information. Sampling design: describes how to choose a sample from a population. Inference: drawing conclusions from information about population from what we know about the sample. Convenience sample: sampling the closest individuals at hand, not effective and creates bias: bias: systemically favouring certain outcomes. Voluntary response sample: lets individuals choose whether to participate or not creates bias. Stratified and multistage combine srs, srs is a building block. Response bias: depends on interviewer, recency effect, withholding information. Wording of questions: different wording of questions can affect answers. Individuals studied are often called subjects or experimental units: treatment: any specific experimental condition applied to the subject, factors explain variables in experiments.
