Contents - Index

Constant Protection

Constant protection means that the protection provided by the sampling plan is the same for all situations.  The protection does not depend on the quality of any previous lots nor does it vary based on other circumstances.  The following types of sampling plans provide constant protection:
  • Single Sampling Plan
  • Double Sampling Plan
  • Multiple Sampling Plan
  • Variables Single Sampling Plan For Defective Units - when standard deviation is know or 1 spec
     
    When the protection is constant, a single OC Curve completely describes the protection provided by the sampling plan and the protection can be adequately summarized by the AQL and LTPD.  When the protection varies, multiple OC curves are required including the Stationary OC Curve, Maximum OC Curve and Minimum OC Curve.