A portion of material selected from a larger quantity of material. The term needs to be qualified, e.g. @[email protected], @[email protected], @[email protected], bulked sample, @[email protected] The term 'sample' implies the existence of a @[email protected], i.e. the results obtained on the portions taken are only estimates of the concentration of a @[email protected] or the quantity of a property present in the parent material. If there is no or negligible @[email protected], the portion removed is a @[email protected], aliquot or specimen. The term 'specimen' is used to denote a portion taken under conditions such that the sampling variability cannot be assessed (usually because the population is changing), and is assumed, for convenience, to be zero. The manner of selection of the sample should be prescribed in a sampling plan.