Construction of Quick Switching Variables Sampling System Indexed by Crossover Point Dr. D. SENTHILKUMAR 1* SR. SATHYA MOHAN RAJ 2 B. ESHA RAFFIE 2 1 Associate Professor, Department of Statistics, PSG College of Arts & Science, Coimbatore -641 014 2 Research Scholar, Department of Statistics, PSG College of Arts & Science, Coimbatore -641 014 Abstract The Quick Switching Sampling System by attributes was devised by Romboski(1969). He has studied a new system, comprising normal and tightened plans, called a Quick Switching System (n;c T ,c N ) [(n,c N ) and (n,c T ) are normal and tightened single sampling plans, respectively, with c T <c N ], proposed by Dodge (1967). In this Paper, Designing Quick Switching Variables Sampling System [QSVSS (n; k N , k T )] indexed by Crossover Point is presented. The method of designing the plan based on the given p c and h c is provided. Table yielding plans for given set of entry parameters namely p c , Crossover Point and h c . Keyword: Quick Switching Sampling System, Variable Sampling Plan, OC Function, Crossover Point and Relative Slope 1. Introduction Dodge (1967) has proposed a new type of sampling plan namely Quick Switching Sampling System and investigated by Romboski (1969), Govindaraju (1991), Deveraj Arumainayagam (1991) and Taylor (1992). Romboski introduced QSS-1 (n;c N ,c T ) which is a QSS-1 with single sampling plan as a reference plan [(n,c N ), (n,c T ) are respectively the normal and tightened single sampling plans with c T <c N ]. Palanivel(1999) has studied the contributions to the study of designing of Quick Switching Variables System and Devaraj Arumainayagam and Soundararajan (1996) introduced a new designing methodology for Quick Switching attribute sampling schemes, indexed by an entry parameter called the Crossover Point (COP). The significance of the COP and the properties of the Operating Characteristic (OC) with respect to it are studied and the necessary tables constructed. . In this paper, Quick Switching Variables Sampling System [QSVSS(n σ ;k N ,k T )] is considered and procedure and table are developed for the selection of the scheme, indexed by a new criterion called the Crossover Point. 2. QSS Variables Sampling System of type QSVSS (n;k N ,k T ) The conditions and the assumptions under which the QSVSS scheme can be applied are as follows: 2.1 Conditions for application • Production is steady so that results on current, preceding and succeeding lots are broadly indicative of a continuing process. • Lots are submitted substantially in the order of production. • Normally lots are expected to be essentially of the same quality. • Inspection is by variables, with quality defined as the fraction non-conforming. 2.2 Basic Assumptions • The quality characteristic is represented by a random variable X measurable on a continuous scale. • Distribution of X is normal with mean and Standard deviation. • An upper limit U, has been specified and a product is qualified as defective when X>U. [when the lower limit L is Specified, the product is a defective one if X<L]. • The Purpose of inspection is to control the fraction defective, p in the lot inspected. Dr. D. Senthilkumar et al. / International Journal of Engineering Science and Technology (IJEST) ISSN : 0975-5462 Vol. 4 No.02 February 2012 419