PSYC 2520 Chapter Notes - Chapter 9: Normative Social Influence, Confidence Interval, Observational Error
7 Dec 2016
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Randomized laboratory-type experiments that use opportunity samples have a restricted sample of participants but usually have a high degree of control over the variables of interest. Researchers who do survey studies select the potential respondents using special sampling procedures in order to generalize their descriptive findings to a specific larger population. Probability sampling implies that randomness enters into the selection process at some stage so that the laws of mathematical probability apply; probability refers to the mathematical chance of an event"s occurring. Two important statistical requirements of a probability sampling plan are (a) that the sample values be unbiased and (b) that there be stability in the samples. To be unbiased, the values produced by the sample must, on average, coincide with the true values of the population. Stability means that there is not much variability in the sample values.
