Statistical Sciences 2244A/B Lecture Notes - Lecture 5: Frequentist Probability, Conditional Probability
5 Oct 2016
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Document Summary
A measure of the long run relative frequency of an event occurring, in identical repeated trials. Classical approach: make an assumption about the theoretical probabilities: # of ways x can occur/ # of different simple events, we often think that each possibility has the same chance of occurring. Law of large numbers: the relative frequency probability of an event tends to approach the actual probability as a procedure is repeated: as we perform and increasing number of trials the probability approaches the actually probability. Mutually exclusive (disjoint) events: cannot occur at the same time. Conditional probability: probability with conditions applied: e. g. A graduate student, if we know she"s female: multiplication rule, p(g|f) = p(g and f) / p(f) = ((149+159)/2226) / (1145/2226) = 0. 268. Prob of male and undergrad: we can use the multiplication rule again: P(m and u) = 645/2226 = we can rearrange the multiplication rule again.
