h6 due november 21

h6 due november 21 - company adopts a new system? C)...

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NEW YORK UNIVERSITY DEPARTMENT OF ECONOMICS ECON-UB.18.011: Statistics, Fall 2011 HOMEWORK 6 DUE MONDAY NOVEMBER 21 2011 BEFORE 5PM in your TA’s mailbox on the 6th f oor, 19 West 4th Street . Problem 1 An insurance company is considering settling small claims by mail rather than by the personal attention of agents, hoping thereby to reduce the time of settling such claims. Under the old system claims were settled with a mean time of 33 2 days. The company decides that the new system is worth adopting if it will reduce the mean time to less than 30 days. The company obtains a random sample of 900 small claims by the new system and f nds that for this sample =29 4 days and =8 2 days. Should the company adopt a new plan? A) Fo rmu la teth i sa sahypo the s i ste
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Unformatted text preview: company adopts a new system? C) Compute of the test and interpret it. D) What would be your conclusion if signi f cance level were 01 instead of 05 ? 1 Problem 2 Weight Watchers claims that those people who use their program lose an average of 46 pounds. A sample of 100 dieters lost an average of 44 pounds, with a standard deviation of 9 pounds. A) Is the Weight Watchers claim is supported by the data? Formulate and test the appropriate hypothesis assuming =10%. B) What is the lowest at which the claim could be rejected? Carefully explain. C) Construct a 99-percent con f dence interval for the mean. On the basis of this interval evaluate whether the Weight Watchers claim is supported by the data. D) Compare and carefully discuss your answers to A), B) and C). Problem 3 6.54/347. Problem 4 6.72/355 2...
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h6 due november 21 - company adopts a new system? C)...

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