Kyoto DA-640, Руководство по эксплуатации

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9. Additional Information
71 DA-650/-645/-640
Uncertainty
Uncertainty is the measure of dispersion (reliability) of measurement results.
Unification of expression and computation method has been initiated by the
International Committee of Weights and Measures (CIPM), and as the results,
in 1993, the International Standard Organization and seven other
international institutes co-edited ””Guide to the Expression of Uncertainty in
Measurement””(GUM), where the word Uncertainty is used.
Traceability
The accuracy of measurement results can be traced, linked or related up to
the national or international standard.
Measuring instruments are calibrated by standard equipment, which is
calibrated by further accurate instrument (less uncertainty). If this process of
searching calibration continues, finally it reaches the national standard. When
the accuracy of a measuring instrument can be traced back to the national or
international standard, it is called traceable.
When the reference substance used in the analytical instrument is traceable,
the instrument can be defined as traceable to national standard.
Density/Specific Gravity Meters of the DA-6xx series are scientific instruments
traceable to the Japanese national standard.
Average (mean value)
The mean value is batch calculated by averaging dispersed measurand.
n
X X X
X
n 2 1
+ ⋅ ⋅ ⋅ + +
=
Standard Deviation
Expressed by ı or s showing dispersion of statistics or random variable:
( )
1 -
2
1
n
X Xi
SD
n
i
¦
−
=
=
RSD (Relative Standard Deviation)
RSD is SD divided by Mean, showing how dispersed against the average. RSD
is the same as Coefficient Variable (CV).
(%) 100 ×
X
SD
RSD
=