In order to set-up a quality control plan for a metal stamping process, a manufacturer wishes to estimate the mean length of the metal parts produced by the process during the past 24 hours. a) How many metal parts should be sampled in order to estimate the population mean to within 0.1 millimeter with 90% confidence? Previous studies of this process have indicated that the standard deviation of lengths of parts produced by the stamping operation is 2 millimeters. (4 Points) b) If management requires that be estimated to within 0.1 millimeter and that a sample size of no more than 100 be used, what is the maximum confidence level that could be attained for a confidence interval that meets management's specifications? (3 Points)