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montgomerykarloxc24x
montgomerykarloxc24x
05.05.2020 • 
Engineering

A civil engineer is analyzing the compressive strength of concrete. The compressive strength is approximately normal distributed with variance 1000 psi2. A random sample of 12 specimens has a compressive strength of 3273, 3229, 3256, 3272, 3201, 3247, 3267, 3237, 3286, 3210, 3265, and 3273 psi. (a) Test the hypothesis that the average compressive strength is 3500 psi. Use a fixed level test with 0.01. (b) What is the smallest level of significance at which you would be willing to reject the null hypothesis? (c) Construct a 95% two-sided IC at medium-force compression. (d) Construct a 99% two-sided IC at medium-force compression. Compare the width of this confidence interval with the width of that found in part

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