Jose De Costa, director of manufacturing at Delta Plastics, sat at his desk looking at the latest production quality report, showing the number and type of product defects per week. He was faced with the task of evaluating production quality for products made with two different materials. One of the materials was new and called "super plastic" due to its ability to sustain large temperature changes. The other material was the standard plastic that had been successfully used by Delta for many years.

The company had started producing products with the new "super plastic" material only a month earlier. Jose suspected that the new material could result in more defects during the production process than the standard material they had been using. Jose had been opposed to starting production until R&D had fully completed testing and refining the new material. However, the CEO of Delta had ordered production despite objections from manufacturing and R & D. Jose carefully looked at the report in front of him and prepared to analyze the results.

1) Prepare a 3-sigma control chart for both production processes, using the new and standard material (use quality report in Delta plastics inc, Case A, Chapter 5 of Opreations management). Are both processes in control? What can you conclude?

2) Are both materials equally subject to the defects?

3) Given your findings, what advice would you give Jose?