Unilateral Tolerance Capability Calculation


Stop X-bar/R Madness!!
Capability indices and calculations are tough enough as it is, but a common approach of using Cpu or Cpl ("half Cpk's") is statistically incorrect. It assumes the data is normal - which is unlikely as you approach the physical limit (0 for form characteristics, such as roundness, concentricity, etc.). Check out the attached for further discussion (Updated 12-02-17).