b. The solid horizontal line through the center of the process control chart represents the target
or Mean line (figure 26). It (target line) represents the central gamma or the optimum gamma desired
for the process.
c. The broken lines (figure 27) represent the control limits of the process. The area between
these lines is the maximum variation (above and below the target line) permissible to maintain the
desired quality in the end product.
Figure 27 illustrates the basic construction of any control chart. The actual number value these