Using Probability to Identify Unlikely Events.

Chapter 4, Problem 30

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Using Probability to Identify Unlikely Events. In Exercises 2936, consider anevent to be unlikely if its probability is less than or equal to 0.05. (This is equivalentto the same criterion commonly used in inferential statistics, but the value of 0.05 is notabsolutely rigid, and other values such as 0.01 are sometimes used instead.) Credit Card Purchases In a survey, 169 respondents say that they never use a creditcard, 1227 say that they use it sometimes, and 2834 say that they use it frequently. What isthe probability that a randomly selected person uses a credit card frequently? Is it unlikely forsomeone to use a credit card frequently? How are all of these results affected by the fact thatthe responses were obtained by those who decided to respond to the survey posted on theInternet by America OnLine?