The fan blades on commercial jet engines must be replaced when wear on these parts indicates too

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The fan blades on commercial jet engines must be replaced when wear on these parts indicates too much variability to pass inspection. If a single fan blade broke during operation, it could severely endanger a flight. A large engine contains thousands of fan blades, and safety regulations require that variability measurements on the population of all blades not exceed s2 = 0.18 mm2. An engine inspector took a random sample of 61 fan blades from an engine. She measured each blade and found a sample variance of 0.27 mm2. Using a 0.01 level of signi­ficance, is the inspector justi­fied in claiming that all the engine fan blades must be replaced? Find a 90% confi­dence interval for the population standard deviation

Please provide the following information.

(a) What is the level of signi­ficance? State the null and alternate hypotheses.

(b) Find the value of the chi-square statistic for the sample. What are the degrees of freedom? What assumptions are you making about the original distribution?

(c) Find or estimate the P-value of the sample test statistic.

(d) Based on your answers in parts (a) to (c), will you reject or fail to reject the null hypothesis of independence?

(e) Interpret your conclusion in the context of the application.

(f) Find the requested confi­dence interval for the population variance or population standard deviation. Interpret the results in the context of the application.

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Understandable Statistics Concepts And Methods

ISBN: 9781337119917

12th Edition

Authors: Charles Henry Brase, Corrinne Pellillo Brase

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