Definition of Accuracy, Precision, Accepted Value,
Estimated Value, True Value, Percent Error, Significant Figure
ACCURACY
In the
fields of science, engineering, industry, and statistics, the accuracy of a measurement system is the degree of closeness of
measurements of a quantity to that quantity's actual (true) value.
PRECISION
The precision
of a measurement system, also called reproducibility or repeatability, is the degree to which repeated
measurements under unchanged conditions show the same results. Although the two words precision and accuracy can be synonymous in colloquial use, they are deliberately contrasted
in the context of the scientific method.
ACCEPTED
VALUE
In science, and most specifically chemistry, the accepted value denotes a
value of a substance accepted by almost all scientists and the experimental
value denotes the value of a substance's properties found in a localized
lab.
ESTIMATED
VALUE
In probability theory,
the expected value (or expectation, mathematical expectation,
EV, mean, or first moment) refers, intuitively, to the
value of a random variable
one would "expect" to find if one could repeat the random variable
process an infinite number of times and take the average
of the values obtained.
TRUE
VALUE
A measurement value with no errors. The true value can never be known
with total certainty.
PERCENT
ERROR
The percent
error is a special case of the percentage form of relative change
calculated from the absolute change between the experimental (measured) and
theoretical (accepted) values, and dividing by the theoretical (accepted)
value.
SIGNIFICANT
FIGURE
The significant
figures of a number are those digits that carry meaning contributing to
its precision. This includes all digits except:
·
Certain
leading and trailing zeros which are merely placeholders to
indicate the scale of the number. (Exact rules are explained in the section
"Identifying significant figures".)
·
Spurious
digits introduced, for example, by calculations carried out to greater
precision than that of the original data, or measurements reported to a greater
precision than the equipment supports.
http://xenontics.blogspot.com/