Practice3-1

Practice3-1 - as 5 of the callers are put on hold for 4.8...

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- 1 - BUAD 310 In-Class Practice 1/26/09 1. The Glitzwear catalog is mailed to thousands of people, and these people make (annually) purchases from the catalog, which average $42 and have a standard deviation of $60. a) Assuming that the distribution is normal, find the probability that one person’s purchases will exceed $40. b) Suppose that you would like to obtain a sample of 100 of these people for followup interviews. For a sample of 100, what is the probability that the average annual purchases will exceed $40? 2. A television cable company receives numerous phone calls throughout the day from customers reporting service troubles and from would-be subscribers to the cable network. Most of these callers are put "on hold" until a company operator is free to help them. The company has determined that the length of time a caller is on hold is normally distributed with a mean of 3.1 minutes and a standard deviation of 0.9 minutes. Company experts have decided that if as many
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Unformatted text preview: as 5% of the callers are put on hold for 4.8 minutes or longer, more operators should be hired. a. What proportion of the company's callers are put on hold for at least 4.8 minutes? Should the company hire more operators? b. At this company, 1% of the callers are put on hold for longer than k minutes. Find the value of k . - 2 - 3. The weight of a product is normally distributed with a mean of four ounces and a variance of 0.25 "squared ounces." a) What is the probability that a randomly selected unit from a recently manufactured batch weighs more than 3.75 ounces? b) What is the probability that an average of 16 of these products weighs more than 4.5 ounces? 4. According to the Bureau of Census, 85.1% of adult residents of Arizona have completed high school. What is the probability that no more than 80% of the persons in a simple random sample of 200 adult residents in Arizona have finished high school?...
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Practice3-1 - as 5 of the callers are put on hold for 4.8...

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