The histogram example below shows the diameter of piston rings. The values are between the LSL and above the USL. The process capability indices (Cp and Cpk) are greater than 1.6, so the process is capable of meeting customer requirements.
The histogram example below shows wafer strength. As you can see, the data fits between the spec limits. Cp and Cpk are greater than 1.0 but less than1.33 which is the standard for most manufacturing requirements.
The histogram example below shows another 5 sigma process (Cp and Cpk > 1.66).