Mõõtemääramatus

Mõõtemääramatus, often translated as measurement uncertainty, is a parameter that characterizes the dispersion of the values that could reasonably be attributed to the quantity being measured. It is an essential concept in metrology, the science of measurement, and is used to express the reliability of a measurement result.

Measurement uncertainty is not the same as measurement error. Error is a single value that describes the difference between a measured value and the true value of a quantity. However, the true value is usually unknown, so error cannot be precisely determined. Uncertainty, on the other hand, quantifies the doubt about the measurement result.

The International Bureau of Weights and Measures (BIPM) defines measurement uncertainty as the "parameter, associated with the result of a measurement, that characterizes the dispersion of the values that could reasonably be attributed to the quantity being measured." It is typically expressed as a standard deviation or a multiple of a standard deviation, often referred to as the expanded uncertainty.

There are two main sources of uncertainty: Type A and Type B. Type A uncertainty is evaluated by statistical methods, such as analyzing replicate measurements. Type B uncertainty is evaluated by means other than statistical analysis of a series of observations, such as using information from calibration certificates, manufacturer's specifications, or expert judgment.

Understanding and quantifying measurement uncertainty is crucial for making informed decisions based on measurement results, for comparing results from different laboratories or measurement systems, and for ensuring the quality and consistency of measurements across various fields. It provides a crucial context for any reported measurement value, allowing users to assess its potential accuracy.