409Quiz1 - of a carbide tip follows a normal distribution....

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STAT 409 Fall 2009 Name _________________________ Quiz 1 (3 points) Be sure to show all your work, your partial credit might depend on it. No credit will be given without supporting work. 1. Metaltech Industries manufactures carbide drill tips used in drilling oil wells. The life of a carbide drill tip is measured by how many feet can be drilled before the tip wears out. Metaltech claims that under typical drilling conditions, the life
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Unformatted text preview: of a carbide tip follows a normal distribution. Suppose that certain regulations require the variance of the lifetimes to be no more than 12 feet 2 . Metaltech examines a random sample of 25 carbide tips to test whether these regulations are met. Suppose Metaltech decided to use a 5% level of significance and the observed sample mean is 30.5 feet with the sample variance 16 feet 2 . Perform the appropriate test....
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This note was uploaded on 10/12/2011 for the course STATISTICS stat 410 taught by Professor Stepanov during the Spring '11 term at University of Illinois, Urbana Champaign.

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