Sampling

The definition of the term “sample” is expressed as “a portion of the whole, selected in such a way as to be truly representative of the whole.” Some additional explanations for this definition include: (a) no sample truly represents all the respects of the whole consignment or population; (b) the sample is always different from the whole consignment, even for the parameters of interests; (c) the sample will only be adequate for the determination of certain elements; and (d) the sample will only be adequate for some analytical techniques (Smith and James, 1981). The sole objective of sampling is to reduce the mass of a target material without significantly changing its other properties, either by taking increments from flowing streams of a material or by splitting when the whole lot of the material can be handled (Gy, 1998).