Statistical Sciences 2037A/B Chapter Notes - Chapter 4: Randomized Experiment, Dependent And Independent Variables, Sampling Frame
4 Jan 2013
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Chapter 4 how to get a good sample. Sample survey is a subgroup of a large population that is questioned on a set of topics. The results are used like they represent a larger population. An experiment measures the effects of manipulation on the environment in some way. A randomized experiment is when the manipulation is assigned to participants on a random basis. The explanatory variable is the result of the feature being manipulated. Randomized experiments allow us to determine cause and effect. The randomizing is to make the groups approximately equal to each other. Differences in the outcome that are large enough can rule out natural variability. Observational study is when the manipulation occurs naturally. Reliance on natural manipulation disables us from finding cause and effect because it is hard to have a control group. Case-control studies attempt to include a control group. An advantage to observational studies is that participants just do what they do naturally.
