MGT 3501 Lecture Notes - Lecture 11: Statistical Process Control, Standard Deviation
Document Summary
How far away the data is from the average. The smaller the standard deviation is, the more under control the process is. Range of variation that a process is able to maintain. Range of variation that is considered acceptable by the designer or customer. If sl > pcl: process is capable (incapable/capable of being defect free) Can"t have data outside of usl or below lsl. Process 1 under control, so capable of being defect free. As long as the sl is outside of the pcl, it"s capable. Can never have data points outside of the pcl. But, if the sl is inside of pcl, can have data points on the outside of the sl. Outside of sl = defects, process is incapable of being deflect free. A process is consistent if its standard deviation is small. A process is accurate if its average performance is close to the target. Once consistency is figured out, it"s much easier to improve accuracy.
