# Stats: Chapter 10

 Chance/Random Phenomenon Has unpredictable behavior in the short run but has a regular and predictable pattern in the long run Probability Studies the likelihood of occurrence of random events in order to predict the behavior of defined systems.Only describes what happens in the long run Sample Space S The set of all possible outcomes in a random phenomenonThe set of all outcomes are caleld events1 event is the subset of the sample space Probability Model Description of a random phenomenon consisting of a sample space S and a way of assigning probabilities to events Probability Rules A number between 0 - 1 is a probability numberAll possible outcomes together must have a probability of oneIf two events have no outcomes in common the probability that one or the other occurs is the sum of their individual probabilitiesThe probability that an event occurs is 1 minus the probability that the event does not occur e.g. If event 1 occurs 50% of the time and a diff event occurs 25% of the time, then the chance of one or the other occuring is 75% Probability numbers. What does 0, 0.5, and 1 mean? 0 = never occurs1 = always occurs0.5 occurs half the trials 0 < P(A) <= 1 A number between 0 - 1 is a probability number P(S) = 1 The sample space S always equals 1 P(A or B) = P(A) + P(B) If A and B are disjoints if they have no outcomes in commonThe chance of one of them occuring is the sum of the two probabilities P(A does not occur) = 1 - P(A) The probability of an event that does not occur is 1 - the probability that the event does occur Discrete Probability Model A model with a finite sample (has limits)The prob of any event is the sum of the probabilities of all the values that make up the eventThis model assigns each of these values a probability between 0 and 1 such that the sum of all the probabilities is 1 Continuous Probability Model Assigns the probabilities as areas under a density curveThe probability of any event is the area under the curve above the values that make up the event Random Variable A variable whose value is a numerical outcome of a random phenomenon Probability Distribution The random variable X tells us what the possible values of X are and how probabilities are assigned to those values Authormuk.muk ID42312 Card SetStats: Chapter 10 DescriptionChapter 10 definitions Updated2010-10-15T03:53:38Z Show Answers