STAT 2040 Study Guide - Midterm Guide: Probability Mass Function, Poisson Distribution, Binomial Distribution
15 Nov 2016
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Probability that it takes more than (cid:862)a(cid:863) trials for a su(cid:272)(cid:272)ess: Can use if np > 5 and nq > 5. Make correction for continuity by adding or subtracting 0. 5 to/from the value of x, depending on what you want to find. Correction for continuity ignored when n is very large because the bars get really skinny and the p of a bar gets very tiny. Tables for binomial p(x) give cumulative values. The r. v. x is the number of occurrences of a rare and random event. One parameter used: , populatio(cid:374) (cid:373)ea(cid:374). (cid:894) , sa(cid:373)ple mean, often used) Variance of a poisson r. v. is equal to its mean. Poissondistr can approximate a binomial distribution with large n and small p. No. trials not fixed; no. successes is fixed. A: - when n (pop. size) is very large. For a fixed value of n, the closer the value of p is to 0. 50.
