Significant Figures
Evaluate the following
calculation:
147.3 lbs
student
x
454 g
lb.
x
1 Kg
1 x 103 g
x
42 students
=
? Kg
Why is
it that the “exact numbers” , shown in red above, have no bearing on the number of significant figures shown in the result of
the calculation?
Significant
Figures:
an
efficient means of representing the precision
of measured quantities; the precision of measured
quantities is implied.
Exact Numbers:
are not measured
quantities.
Precision is a measure of the reproducibility and the uncertainty
in measured quantities.
Considerations
of uncertainty, of reproducibility, and
of significant figures are irrelevant.