Biology 2244A/B Chapter Notes - Chapter 4: Sample Space
11 Feb 2017
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Use a result from a sample to estimate something about a population. Random samples eliminate bias from the act of choosing a sample, but they can still be wrong because of the variability that results when we choose at random. If the variation when we take repeat samples from the same population is too great, we (cid:272)a(cid:374)"t trust the results of a(cid:374)y o(cid:374)e sa(cid:373)ple. Describes what happens in very many trials: the proportion in a small or moderate number of tosses can be far from the probability, probability describes only what happens in the long run. Called frequentist approach to defining probabilities b/c we rely on the relative frequency of one particular outcome among very many observations of the random phenomenon. Chance behaviour is unpredictable in the short run but has a regular and predictable pattern in the long run: reason why we can trust random samples and randomized comparative experiments.
