33
rological literature about what values of quantities are, and the concept property> is seldom used, but entities such as 1.2345 m or 2.34 kg are uncontroversially recognized as examples of values of quantities. Hence we introduce the subject here only for quantities with a unit, leaving to Chap. 6 the general treatment of
nonquantitative properties and their values.
17
In the simplest case, in which measurement uncertainty can be omitted, a measurement result (JCGM, 2012: 2.9) is
18
measurand measured value of aquantity
=
a relation that we call the Basic Evaluation Equation and whose meaning is analyzed in Chap. 5.
19
A symbolic form of a Basic Evaluation Equation is
Q a q m
[ ] =
For example:
Length of rod a
m
= 1 2345
.
or in symbols
L a
[ ] = 1 2345
.
m
as depicted in Fig. 2.8.
The relation can be then written more analytically as
Q a x
[ ] = q ref
17 Values of properties could be, for example, cube, in a given set of shapes (a value of the nominal
property shape), or second preferred, in a given sequence of preferences (a value of the ordinal
property preference).
18 As customary, we write this relation as an equality, =, instead of as an equivalence, ≅, or as a
similarity, ≈. The nature of this relation is discussed in Chap. 5. More completely, a measurement
result must also include information of some sort on the measurement uncertainty (JCGM, 2012:
2.26), a condition that in a following section we show to be a critical characteristic of measurement. Note that, together with “measured value”, the GUM also uses the term “estimated value”
(JCGM, 2008: 2.2.4), with a more explicit statistical-probabilistic connotation.
19 The term “evaluation” inherits the ambiguity of “value”, as mentioned in Footnote 7. We are using
it here in the technical, non-axiological sense of attribution of a value to the property of an object.
Fig. 2.8 The abstract structure of measurement (fourth version, in the case of quantities)
2.2 The abstract structure of measurement
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