APA 2534 Lecture Notes - Lecture 11: Sampling Frame, Systematic Sampling, Convenience Sampling
6 Mar 2017
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Document Summary
The process of choosing sample from the population: based on theories of probability from statistics. Primary goal is: representing the population: making inferences to the larger population. Key concepts: sampling frame (target population, sampling ratio (n/n, sampling error. Sample is biased if it does not represent the population from which it was selected. Sources of bias: not using a random method to pick the sample, the sampling frame, human judgement that selects one group over another, non-response, some people in the sample fail to participate which skews the data. Probability: simple random, systematic, stratified, multiple cluster. Each element has the same probability of being selected: each combination of elements has the same probability of being selected. Random sampling but with a shortcut: calculate a sampling interval (e. g. , every 3rd person, do not use if the elements within a sample are patterned, a potential problem with systematic sampling: periodicity.
