STAB22H3 Lecture Notes - Lecture 1: Empirical Probability, Sample Space, Block Design
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STAB22H3 Full Course Notes
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An observational study observes individuals and measures variables of interest but does not attempt to influence the response. An experiment imposes a treatment on individuals in order to observe their response. observational studies are valuable for discovering trends and possible relationships. however, it is not possible for observational studies to demonstrate a causal relationship. when our goal is to understand the cause and effect, experiments are the only source of fully convincing data. Look at a bunch of people, find out if they exercise and how much, ask them to rate their insomnia. Suppose the people who exercise more suffer less from insomnia. Maybe: but this is only an association, not cause and effect. This is an example of an observational study. Assesses association but not cause and effect (like correlation). May help identify variables that have an effect. But does not prove cause and effect. Retrospective study looking back , like one above:
