Sensitivity and Uncertainty Analysis Flashcards
Absolute error (of a measuring instrument)
The difference between the value of the measured quantity obtained by using a measuring instrument and the true (but unknown) value of the measured quantity.
Absolutely constant elementary error
An elementary error that retains the same value in repeated measurements performed under the same conditions. The value of an absolutely constant error is unknown but its limits can be estimated.
Accuracy of measurement
A qualitative expression of the closeness of the result of a measurement to the true value of the measured quantity.
Accuracy of a measuring instrument
The ability of a measuring instrument to produce measurements whose results are close to the true value of the measured quantity.
Combined measurement
Measurement of several quantities of the same kind, using results from (and/or combinations of) direct measurements.
Conditionally constant elementary error (of a measurement)
An elementary error, having definite limits, which varies in repeated measurements performed under the same conditions or with different measuring instruments of the same type. These limits can be calculated or estimated.
Dead band
Maximum interval through which a stimulus may be changed in either direction without producing a change in the response of a measuring instrument.
Drift
A slow variation in time of the output of a measuring instrument, independently of the respective stimulus.
Elementary error (of a measurement)
A component of error or uncertainty of a measure- ment associated with a single source of inaccuracy of the measurement.
Error (of a measurement)
The deviation of the result of a measurement from the true value of the measured quantity; the error is expressed in absolute or relative form.
Inaccuracy (of a measurement)
A qualitative characteristic of the deviation of a measure- ment result from the true value of the measured quantity. Quantitatively, inaccuracy can be characterized either as a measurement error or as a measurement uncertainty.
Indirect measurement
A measurement in which the value of the measured quantity is cal- culated by using measurements of other quantities that are connected to the measured quantity by a known relation.
Intrinsic error
The error of a measuring instrument, determined under reference condi- tions.
Measurement
The set of experimental operations that are performed using technical products (measuring instruments) for the purpose of finding the value of a physical quantity.
Measuring instrument
A technical product with standardized metrological characteristics.
Measuring standard
A measuring instrument intended to materialize and/or conserve a unit of a physical quantity in order to transmit its value to other measuring instruments.
Metrology
Science of measurement: an applied science that includes knowledge of mea- surements of physical quantities.
Normal operating conditions
Conditions within which a measuring instrument is designed to operate so that its metrological characteristics lie within specified limits.
Primary standard
A measuring standard that has the highest accuracy (in a country).
Random error (of a measurement)
A component of the inaccuracy of a measurement that varies in an unpredictable way in the course of repeated measurements of the same measured quantity under the same conditions.
Relative error
Absolute error divided by the true value of the measured quantity. In practice, the true (but unknown) value is replaced by the measurement result.
Repeatability of a measurement:
The closeness of agreement among several consecutive mea- surements of the same quantity, performed under the same operating conditions with the same measuring instruments, over a short period of time.
Reproducibility of a measurement
The closeness of agreement among repeated measure- ments for the same measured quantities performed in different locations, under different operating conditions, or over a long period of time.
Resolution
The smallest, still distinguishable interval between two adjacent values of the output signal of a measuring instrument.
Result of measurement
The value obtained by measurement of a quantity. The measurement result is expressed as a product of a numerical value and a proper unit.
Sensitivity of a measuring instrument
The change in the response of a measuring instrument divided by the corresponding change in the stimulus.
Systematic error (of measurement)
A component of the inaccuracy of measurement that remains constant or varies in a predictable way in the course of repeated measurements of the same measured quantity.
True value
The value of a measured quantity that (if it were known) would ideally reflect, qualitatively and quantitatively, the respective property of the quantity of interest.
Uncertainty of measurement
An interval within which the true value of a measured quantity would lie with a given probability. Uncertainty is defined with its limits and corresponding confidence probability, and can be expressed in absolute or relative form.
