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Sampling Bias Terminology. Mrs. Clements. Census. An official, usually periodic enumeration of an entire population, often including the collection of related demographic information. Robert Goldenkoff, 2010 Census Video. Sample.
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Sampling Bias Terminology Mrs. Clements
Census • An official, usually periodic enumeration of an entire population, often including the collection of related demographic information. • Robert Goldenkoff, 2010 Census Video
Sample • a group drawn from a population and used to estimate the characteristics of the population. • A sample is used because a census is expensive, time –consuming and complex.
Undercoverage(Selection) Bias GALLUP • occurs when the way that the sample is selected systematically excludes part of the population • Literary Digest: The Poll that Changed Polling VERSUS
Sampling Frame • list of possible subjects who could be selected in a sample • If the sampling frame is not equal to the population, the sample will be biased in the same way the sampling frame is bias. S A M P L I N G
Convenience (Judgmental) Sample • choosing the individuals that are easiest to reach • Mall Surveys • This is also an example of selection bias.
Response Bias Occurs when the response of the sample is swayed by a factor other than the variable at hand • Wording of the question • Honesty • Order of the choices • Demeanor of the interviewer
Non-Response Bias occurs when responses are not obtained from all individuals selected for inclusion in the sample • mail surveys • telephone surveys
Voluntary Response Bias • self-selection • represents members of the population with strong opinions • Dancing with the Stars