An aircraft manufacturer needs to buy aluminum sheets with an average thickness of 0.05 inch. The manufacturer knows that significantly thinner sheets would be unsafe and considerably thicker sheets would be too heavy. A random sample of 100 sheets from a potential supplier is collected. The thickness of each sheet in this sample is measured (in inches) and recorded in the file P09_07.xlsx.
a. Identify the null and alternative hypotheses for this situation.
b. Based on the results of an appropriate hypothesis test, should the aircraft manufacturer buy aluminum sheets from this supplier? Explain why or why not.
c. For which values of the sample mean (i.e., average thickness) would the aircraft manufacturer decide to buy sheets from this supplier? Assume a significance level of 5% in answering this question.