Q-1. List Shewhart’s two types of variation. What are they also called?
Q-2. Define “in statistical control.”
Q-3. Explain briefly what an x -chart and an R -chart do.
Q-4. What might cause a process to be out of control?
Q-5. List five steps in developing and using x -charts and R -charts.
Q-6. List some possible causes of assignable variation.
Q-7. Explain how a person using 2-sigma control charts will more easily find samples “out of bounds” than 3-sigma control charts. What are some possible consequences of this fact?
Q-8. When is the desired mean, m , used in establishing the center-line of a control chart instead of x ?
Q-9. Can a production process be labeled as “out of control” because it is too good? Explain.
Q-10. In a control chart, what would be the effect on the control limits if the sample size varied from one sample to the next?