plugin-Chapter 18 Students - Probability Models CHAPTER 18 PROBABILITY MODEL A probability model for a random process describes all the possible

plugin-Chapter 18 Students - Probability Models CHAPTER 18...

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CHAPTER 18 Probability Models
PROBABILITY MODEL A probability model for a random process describes all the possible outcomes and says how to assign probabilities to any collection of outcomes. Flip a coin H T Probability 0.5 0.5
PROBABILITY RULE A Any probability is a number between 0 and 1. A probability can be interpreted as the proportion of times that a certain event can be expected to occur. If the probability of an event is more than 1, then it will occur more than 100% of the time (Impossible!).
PROBABILITY RULE B All possible outcomes together must have probability 1. Because some outcome must occur on every trial, the sum of the probabilities for all possible outcomes must be exactly one. If the sum of all of the probabilities is less than one or greater than one, then the resulting probability model will be incoherent.
PROBABILITY RULE C The probability that an event does not occur is 1 minus the probability that the event does occur. As a jury member, you assess the probability that the defendant is guilty to be 0.80. Thus you must also believe the probability the defendant is not guilty is 0.20 in order to be coherent (consistent with yourself).

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