Expanded Uncertainty

{
  "id": "MLC-T-ENV-010391",
  "term": "Expanded Uncertainty",
  "field": "Environment",
  "definition": "1. Measure of uncertainty that defines an interval about the measurement result y within which the value of the measurand Y can be confidently asserted to lie. Although the combined standard uncertainty uc is used to express the uncertainty of many measurement results, for some commercial, industrial, and regulatory applications (e.g., when health and safety are concerned), what is often required is an expanded uncertainty, suggested symbol U, and is obtained by multiplying uc(y) by a coverage factor, suggested symbol k. Thus U = kuc(y) and it is confidently believed that Y is greater than or equal to y - U, and is less than or equal to y + U, which is commonly written as Y = y ± U.\n\n2. Quantity defining an interval about the result of a measurement that may be expected to encompass a large fraction of the distribution of values that could reasonably be attributed to the measurement.",
  "references": [
    "40 CFR 72.2 (CFR 2013)",
    "Adapted from Forum on Environmental Measurements (FEM) Glossary"
  ],
  "url": "https://mlchart.com/terminology/environment/expanded-uncertainty/"
}