ISO 11222:2002 空気質 — 空気質測定の時間平均の不確かさの決定 | ページ 6

3.1

arithmetic mean

average

sum of values divided by the number of values

[SOURCE:ISO 3534-1:1993, 2.26]

3.2

combined standard uncertainty

standard uncertainty of the result of a measurement when that result is obtained from the values of a number of other quantities, equal to the positive square root of a sum of terms, the terms being the variances and covariances of these quantities weighted according to how the measurement result varies with changes in these quantities

[SOURCE:GUM:1995, 2.3.4]

Note 1 to entry: The (combined) standard uncertainty of the result of a measurement is the positive square root of its mean square uncertainty.

3.3

covariance

measure of the statistical dependence of two observable quantities which may be considered as random variables

Note 1 to entry: Two observable quantities have a non-zero covariance if they are correlated, i.e. a change in one quantity results in a change in the other quantity.

3.4

coverage factor

numerical factor used as a multiplier of the combined standard uncertainty in order to obtain an expanded uncertainty

[SOURCE:GUM:1995, 2.3.6]

3.5

expanded uncertainty

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 measurand

[SOURCE:GUM:1995, 2.3.5]

Note 1 to entry: If the expanded uncertainty of a result X of measurement on the level of confidence p is given by U_p ( X ), the unknown true value of X is expected with probability p to be located within the interval [ X − U_p ( X ); X + U_p ( X )].

3.6

influence quantity

quantity that is not the measurand but that affects the result of the measurement

[SOURCE:GUM:1995, B.2.10]

3.7

mean square uncertainty

square of the combined standard uncertainty of a measurement result

Note 1 to entry: The mean square uncertainty of a measurement result may also be estimated by the mean square deviation of the measurement result from material measures of the “true” value.

3.8

measurand

particular quantity subject to measurement

[SOURCE:VIM:1993, 2.6]

Note 1 to entry: In the field of air quality monitoring, the measurand can be a highly varying function of time.

3.9

measuring system

complete set of measuring instruments and other equipment with operating procedures for carrying out specified air quality measurements

Note 1 to entry: The operating procedure includes or refers to a specification of the calibration routine, if calibration of the measuring system is needed for its proper operation.

3.10

model equation

mathematical model of the measurement that transforms the set of (repeated) observations performed into the measurement result

3.11

number of degrees of freedom

in general, the number of terms in a sum minus the number of constraints on the terms of the sum

[SOURCE:GUM:1995, C.2.31]

3.12

random variable

a variable that may take any of the values of a specified set of values and with which is associated a probability distribution

[SOURCE:GUM:1995, C.2.2]

3.13

reference material

material or substance one or more of whose property values are sufficiently homogeneous and well established to be used for the calibration of an apparatus, the assessment of a measurement method, or for assigning values to materials

[SOURCE:VIM:1993, 6.13]

3.14

reference standard

standard, generally having the highest metrological quality available at a given location or in a given organization, from which measurements made there are derived

[SOURCE:VIM:1993, 6.6]

3.15

result of a measurement

value attributed to a measurand, obtained by measurement

[SOURCE:VIM:1993, 3.1]

3.16

standard

material measure, measuring instrument, reference material or measuring system intended to define, realize, conserve or reproduce a unit or one or more values of a quantity to serve as a reference

[SOURCE:VIM:1993, 6.1]

3.17

standard deviation

positive square root of the variance of the random variable considered

Note 1 to entry: Adapted from the GUM:1993, C.2.12.

3.18

standard uncertainty

uncertainty of the result of a measurement expressed as a standard deviation

[SOURCE:GUM:1995, 2.3.1]

3.19

time average

mean value of a set of measurement results (air quality data) recorded within a defined time period

3.20

uncertainty

parameter, associated with the result of a measurement, that characterises the dispersion of the values that could reasonably be attributed to the measurand

[SOURCE:VIM:1993, 3.9]

Note 1 to entry: The uncertainty of a result of a measurement may be described by the (combined) standard uncertainty or by an expanded uncertainty on a stated level of confidence.

3.21

variance

central moment of order 2

Note 1 to entry: The variance of a random variable may be defined equivalently as the expected value of the quadratic deviation of the random variable about its expected value.