Dean Door Corporation (DDC) manufactures steel and aluminum exterior doors for commercial and residential applications. The manufacturing operation...

  Construct the appropriate control chart(s) for the data in the table using 3 sigma control limits.  If the process is in control, explain why.  If the process is out of control, explain why and provide likely causes based on the data provided.  In addition, explain how any special causes found might be eliminated.  Note:  Regardless of whether an x-bar and r-chart, a p-chart, or a c-chart is used, put the appropriate sample measures from all three workers on the same chart in the order in which the observations were taken (i.e., you should have one connected line on the graph containing 30 observations).