Determination of Quick Switching System by Attributes under the Conditions of Zero-Inflated Poisson Distribution

Sampling plans, systems and schemes are used to accept/reject the lots when inspecting a series of lots. A sampling system is a grouping of two or more sampling plans with specified rules for switching between the plans for selecting the lots of finished products. Quick Switching System (QSS) is used to make accept or reject decisions when inspecting a series of lots. Quick Switching System require fewer samples for processes running at low levels of defects. QSS is a sampling system with reference to single sampling plan that involves normal and tightened plans by incorporating a switching rule. Quick Switching System can be applied to protect from poor quality and to reduce the cost of inspection. When the production process is monitored well, occurrence of defects in the manufactured products would be rare. The information related to number of defects will have more number of zeros. Under such circumstances, the appropriate probability distribution of the number of defects is a zero-inflated probability distribution rather than the usual probability distribution. A zero-inflated probability distribution (ZIPD) can be defined by a mixture of two distributions. The component distribution associated with the larger mixing proportion would be a distribution which degenerates at zero. In this paper, a study of QSS with reference to Single Sampling Plan using ZIPD is designed and tables are constructed for some set of values of (p1, α, p2, β). Comparison is made with the existing plan and its advantages are highlighted with example.