Exercise 2 (12 marks) As part of the quality-control program for a catalyst manufacturing line, the raw materials (alumina and a binder) are tested for purity. The process requires that the purity of the alumina is to be 85%. A random sample from a recent shipment of alumina yielded the following results (in %): 93.2 87.0 92.1 90.1 87.3 a) Test the requirements of the catalyst manufacturing line using the appropriate hypothesis test (assume = 0.05). 93.6 b) Verify your result in part (a) using the appropriate confidence interval.