Green River Chemical Company customers have complained regarding the sulfate content of the company's product. Every customer allows some sulfate content, but theoretically there should be none. The usual customer specification is 90 parts per million (PPM) sulfate.

The quality control department at Green River feels that there is no problem with sulfate content, which has been averaging just over 50 PPM. The production department estimates that a substantial investment would be required to lower the amount of this contaminant. These two departments, after consulting with the marketing department and customers, suggest that a control chart be set up to monitor sulfate content. Five samples will be tested per day and plotted as one point on the chart.

1) Create the x bar control chart.  Use the data in Table 1 to set up the control limits on your control chart.

2) Graph the data from Table 1 on your control chart.  Does the data appear to be in control?

3) Using the control limits you computed from the data in Table 1, graph the data from Table 2.  Does the process remains in control for the week of April 6-10? 

4)  What is your recommendation?

Attachment:- homework.docx