ISDS 2000 Chapter : Chapter 7 Outline
15 Mar 2019
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Time and cost - a sample can provide results more quickly and for a lower cost. (example: long version of the census form: feasibility in some cases, taking. When sampling, you must have a listing of items that make up the population. C. types of samples: ****probability sample sample in which items are selected based upon known probabilities. Example: simple random sample: nonprobability sample a sample in which the items have unknown probabilities of being selected. Necessary when making conclusions about the population, that is, for statistical inference: sources of error that threaten. Example: nonsampling error (referred to as bias) error that results in a distortion of conclusions, nonresponse error error incurred when some subjects refuse to respond to a survey. Example: estimating percentage of car crashes that involve alcohol. Bac test: coverage error occurs when certain items are excluded from the sampling frame, measurement error when data collected do not reflect the true measures.
