Comparison Between Four Methods to Construction Number of Defectives Control Chart

A quality control chart (also called process chart) is a graph that shows average for the data (output) or the product fall within the common or normal range of variation if the process is under statistical control. The existing study draws Comparison between four methods to construct Number of Defectives Chart. We compare methods to obtain the Number of Defectives chart based on Six sigma, which this makes the method much better than other methods, because the distance between control limits for Number of Defectives chart is based on six sigma which that has the smallest comparison properties than other methods, and that the process is out of control for all charts. It is proposed that the six sigma should be used when monitoring and detecting out of control cases.