COMM 291 Chapter Notes - Chapter 3: Statistical Parameter, Sampling Bias, Stratified Sampling
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COMM 291 Full Course Notes
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Comm291 - chapter 3 - surveys and sampling. Idea 1: examine a part of the whole. Since it is not practical for most to interview whole population of a population, most interview a sample selected from the population. A sample survey is designed to ask questions of a small group of people in hopes of learning something about the entire population. Must select a sample that is fairy representative of a population. A biased sample has summary characteristics differing from the corresponding characteristics of the population it is trying to represent. Should select individuals for sample at random! Randomization can protect against factors you are not aware of. Protects us from in uences of all feature of the population by making sure that on average the sample looks like the rest of the population. Nobody can guess the outcome before it happens. When we want things to be fair, usually some underlying set of outcomes will be equally likely.
