The scope of this supplement is to specify procedures for evaluation of uncertainties in individual test measurements, arising from both random errors and systematic errors, and for the propagation of random and systematic uncertainties into the uncertainty of a test result. The various statistical terms involved are defined in the Nomenclature (para. 3.1) and Glossary (para. 3.2). The end result of a measurement uncertainty analysis is to provide numerical estimates of systematic uncertainties, random uncertainties, and the combination of these into a total uncertainty with an approximate confidence level.