Multilot Sampling—The Accuracies in Sampling of Large Coal Shipments by Application of the Variance Concept

This paper presents a system for applying the variance concept of coal sampling to routine sampling work. The relation between the design of routine sampling schemes and the resulting accuracy can be found by evaluating the “observed” variance of the coal and the combined variance of sample reduction and analysis. These accuracies can be expressed for large quantities of coal consisting of many “lots,” or barges, or railroad cars, rather than merely for one “lot” as in the existing ASTM specifications.