Statistical Sciences 2244A/B Chapter Notes - Chapter 7: Fetus, Confounding, Stratified Sampling
23 Sep 2016
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Observational study: subject of inquiry is disturbed as little as possible when gathering data. ex. What is the range of gestation times in the prairie dog? or what is the proportion of americans who are overweight? . Experiment: apply treatment or conditions in order to observe the response. The purpose of an experiment is to study whether the treatment causes a change in the response. Population: the population in a statistical study is the entire group of individuals about which we want information. trend: in a time plot, this is a long-term upward or downward movement over time. Sample: a part of the population from which we collect information. We use a sample to draw conclusions about the entire population. It can take different values for different individuals. Experiments rarely use samples from entire population of interest, thus conclusions from the experiment cant always be extended to the whole population.
