4) a) A manufacturing company has ten nominally identical factories producing the same product. One of the operations in the manufacturing process involves milling a cavity out of a plastic block. When examining the recorded metrics from all ten factories, a plot of the number of milled cavities against the cavity depth does not yield a normal distribution. i) What does this information indicate? ii) How could you identify which of the factories is the potential cause of the problem? iii) Describe the steps required in the process of identifying the problematic manufacturing site. b) Consider the manufacturing process of drilling a hole through a steel bar. It has been found that 5% of the holes drilled fail to mean the specified dimensions. As a quality engineer tasked with investigating the issue, construct a cause and effect 'fishbone' diagram stating two logical and specific possible causes under each of the 4M headings of the cause and effect diagram for the poor quality holes drilled. c) Explain why customer focus is considered such an important quality management principle.