COB 191 Study Guide - Midterm Guide: Central Limit Theorem, Normal Distribution, Emv
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Mean = = expected value = e(x) = n i=1. = mean ( = x * rel frequency) 1 xi = value of random variable for ith outcome. P(xi) = probability that the ith outcome will occur n = number of outcomes in the distribuion. 2 = variance = x i n i=1. Ex. when you have two opions: success or failure n ! P(x,n) = ( n x )! x ! p x qn x n: number of trials p: probability of success q: probability of failure x: number of successes. Ex. number of customers to call a hotline. : mean number of occurrences e: 2. 71828 x: number of occurrences. Normal distribuion approximate when sample size is large enough so np>=5. : mean number of occurrences (customers): 1/ e: 2. 71828 a: number of interest. X x2) = x 2 x 1 b a x1: lower end of interval of interest x2: upper end of interval of interest.
