Evaluating uncertainty components: Type B
A Type B evaluation of standard uncertainty is usually based on scientific judgment using all of the relevant information available, which may include:
previous measurement data,
experience with, or general knowledge of, the behavior and property of relevant materials and instruments,
manufacturer's specifications,
data provided in calibration and other reports, and
uncertainties assigned to reference data taken from handbooks.
Below are some examples of Type B evaluations in different situations, depending on the available information and the assumptions of the experimenter. Broadly speaking, the uncertainty is either obtained from an outside source, or obtained from an assumed distribution.