Activities

Types of Errors

02/02/2022
Uncertainty calculation in chemical analysis
Error
measured quantity value minus a reference quantity value.
Systematic error
component of measurement error that in replicate measurements remains constant or varies in a predictable manner.
Random error
component of measurement error that in replicate measurements varies in an unpredictable manner.
02/02/2022
Uncertainty calculation in chemical analysis
Definitions of Uncertainty
Standard uncertainty
measurement uncertainty expressed as a standard deviation.
Combined standard uncertainty
standard measurement uncertainty that is obtained using the individual standard measurement uncertainties associated with the input quantities in a measurement model.
Relative standard measurement uncertainty
standard measurement uncertainty divided by the absolute value of the measured quantity value.
02/02/2022
Uncertainty calculation in chemical analysis
Definitions of Uncertainty
uncertainty budget
statement of a measurement uncertainty, of the components of that measurement uncertainty, and of their calculation and combination.
expanded uncertainty
product of a combined standard measurement uncertainty and a factor larger than the number one.
02/02/2022
Uncertainty calculation in chemical analysis
Measurement of Uncertainty
Uncertainty
non-negative parameter characterizing the dispersion of the quantity values being attributed to a measurand, based on the information used.
Result= Value ± Uncertainty (unite)
Result= 1.20 ± 0.02 mg/g (k=2)
1.20
1.18
1.22
02/02/2022
Uncertainty calculation in chemical analysis
Measurement of Uncertainty
As shown, Result= 100 ± 0.1 (unite)