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Unformatted text preview: Homework 3 (due Feb. 14) 1. An industrial engineer is responsible for testing a big batch of ball bearings whose mean diameter is supposed to be equal to 3.750 mm. She took a sample of size 50, and set the critical values (for the sample mean ¯ x ) for the test at 3.740 mm and 3.760 mm. The standard deviation for the diameter is known to be equal to 0.03 mm. a) What significance level is she using for the test? b) What would the significance level become if she set the critical values to 3.743 and 3.757 mm, respectively? c) What should the critical values be for α = 0 . 05? d) Would she reject the null hypothesis H : μ = 3 . 750 at α = 0 . 05 if the sample mean were equal to 3.741 mm? 2. Consider the situation of problem 1. Assume that the significance level is set at 0.05. a) Find the probability of type II error if the true mean diameter is equal to 3.755 mm. b) What would the type II error probability be if the true mean diameter were 3.760 mm?...
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This note was uploaded on 03/17/2008 for the course IE 121 taught by Professor Perevalov during the Spring '08 term at Lehigh University .
- Spring '08