This file shows a template of Control Chart, which is a tool used to check if a manufacturing or business process is under statistical control. This template shows the control chart of imperfections in a book. In the chart, there are four curves in total, the mean value of the imperfections, the sample mean and the lower and upper control limit. From the chart, we can see the sample mean value fluctuates around the mean value but not beyond the lower and upper control limit, which means the quality of the book is meet the requirement. If the sample mean is beyond the control limit, the printing process may need a control, which is what a control chart is for.