The consideration of variables sampling begun in the third chapter will be generalized in the present one to the treatment of several classes of reported data. Thus we continue with and extend a model of verification based upon statistical testing of quantitative measurement data, both those of inspector and inspectee, with the concomitant possibility of reaching the wrong conclusion: false alarm probabilities are finite. The main conclusion of the chapter, Theorem 4.2, is the variables sampling analog of Theorem 2.1.

The results to follow have been obtained primarily in connection with the analysis of inventory verification in nuclear fuel production and processing plants, where the material to be verified is extremely hazardous and valuable and is present in a wide variety of physical and chemical configurations. Prior to verification the material listed by the facility operator is stratified or classified according to characteristics such as accessibility, degree of purity, similarity of content, available measurement techniques, etc.

Stratification is an important prerequisite for the establishment of efficient sampling plans, not only for nuclear safeguards. For example Welsch (1992) mentions that, in the case of monitoring air pollution from power plants, seven different constituents have to be considered, each requiring its own measurement method.

Nevertheless, this chapter has been written without any one specific example in mind, the wide range of applications of the theory being, we feel, manifest.