01:960:401 Chapter 5: Chapter 5: Probability Distributions
Document Summary
Introduction: prescription for the probability model of an experiment contains two basic ingredients: sample space and the assignment of probability to each elementary outcome. The union of these events is the entire sample space: typically the possible values of random variable x can be determined directly from the description of the random variable without listing the sample space. Probability distribution of a discrete random variable: list of possible values of a random variable x makes us aware of all the eventualities of an experiment as far as the realization of x is concerned. The probability that a particular value of xi occurs is denoted by f(xi). Quantities of f(xi) must all be numbers between 0 and 1 and sum add up to 1: f(xi)=p[x=xi, 0<=f(xi)<=1 for each value xi of x, sum of f(xi)=1. Successes and failures- bernoulli trials: simple probability model can be developed for the chance variation in the outcomes. Population proportion does not need to be known.