COMMERCE 3QA3 Lecture : Commerce 3QA3 Lecture 1
Document Summary
A probability is a number between 0 and 1 representing the likelihood of an occurrence of an uncertain event. If it is 0, event is virtually impossible; if it is 1, event is virtually certain. There are 3 types of probabilities: (1) objective based on symmetry of outcomes. For example, drawing an ace from a deck of cards the probability is 4 / 52 = 1 / 13 (2) objective based on relative frequency in the long run. For example, a process may have a 5% defective rate (3) subjective which represents an individual"s degree of belief. Outcome space is the collection of all outcomes. Uncertain event is a subset of outcome space. Complement is all outcomes not in a certain event. Intersection or joint is a set of outcomes contained in both events. For example, a student getting at least a includes a and a+ Union is contained in at least one of the events.