Not all junk mail comes from businesses. Internet lore is full of familiar scams, such as the desperate foreigner who needs your help to transfer a large amount of money. The scammer sends out 100,000 messages and gets 15 replies. Can the scam artist make a 95% confidence interval for the proportion of victims out there, or is there a problem with the methods of this chapter?
Answer to relevant QuestionsA package of light bulbs promises an average life of more than 750 hours per bulb. A consumer group did not believe the claim and tested a sample of 40 bulbs. The average lifetime of these 40 bulbs was 740 hours with s = 30 ...A phone company launched an advertising program designed to increase the number of minutes of long-distance calls made by customers. To get a sense of the benefits of the program, it ran a small test of the promotion. It ...The research labs of a corporation occasionally produce breakthroughs that can lead to multibillion-dollar blockbuster products. Should the managers of the labs be more worried about Type I or Type II errors? A test of filtering software examined a sample of n = 100 messages. If the filtering software reduces the level of spam to 15%, this test only has a 33% chance of correctly rejecting H0: p ≥ 0.20. Suppose instead of using ...Refer to the analysis of shoppers in Exercise 45. (a) If several of those participating in the loyalty program are members of the same family, would this cause you to question the assumptions that underlie the test in this ...
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