1、 4-1Chapter 4Basic ProbabilityBusiness Statistics4-2Chapter GoalsAfter completing this chapter, you should be able to: n Explain basic probability concepts and definitionsn Use contingency tables to view a sample spacen Apply common rules of probabilityn Compute conditional probabilitiesn Determine
2、whether events are statistically independentn Use Bayes Theorem for conditional probabilities4-34-4Basic Probability Conceptsn Probability the chance that an uncertain event will occur (always between 0 and 1)n Impossible Event an event that has no chance of occurring (probability = 0)n Certain Even
3、t an event that is sure to occur (probability = 1)4-5Assessing ProbabilityThere are three approaches to assessing the probability of an uncertain event:1. a priori - based on prior knowledge of the process2. empirical probability3. subjective probabilitybased on a combination of an individuals past
4、experience, personal opinion, and analysis of a particular situation Assuming all outcomes are equally likelyprobability of occurrenceprobability of occurrence4-6Example of a priori probabilityFind the probability of selecting a face card (Jack, Queen, or King) from a standard deck of 52 cards.Examp
5、le of a priori probabilityWhen randomly selecting a day from the year 2015 what is the probability the day is in January?4-8Example of empirical probabilityTaking Stats Not Taking StatsTotalMale 84 145 229Female 76 134 210Total 160 279 439Find the probability of selecting a male taking statistics fr
6、om the population described in the following table:Probability of male taking statsSubjective probabilityn Subjective probability may differ from person to personn A media development team assigns a 60% probability of success to its new ad campaign.n The chief media officer of the company is less op
7、timistic and assigns a 40% of success to the same campaignn The assignment of a subjective probability is based on a persons experiences, opinions, and analysis of a particular situationn Subjective probability is useful in situations when an empirical or a priori probability cannot be computed4-10Probabilityn Probability is the numerical measure of the likelihood that an event will occurn The probability of any event must be between 0 and 1, inclusivelyCertainImpossible.5100 P(A) 1 For any event A
