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C.
Average Value
In many experiments you will make two
or three determinations of some quantity such as moles or
concentration and will be asked to report
the average value. Because the number of observations
is too small to allow for valid statistical
interpretations, you should use common sense,
especially
if you have some justification for doing
so. If you are aware that you have an error in technique,
obviously that measurement should be discarded.
If, for example, you make three determinations
and find that two of them agree rather
closely while the third is far off (greater than 10%), you
should drop the third and report the average
of the two that agree more closely.
There is one other important point to
keep in mind. Since many of the techniques that you will be
using are new to you, the value obtained
in the last measurement should be better than those
obtained in earlier measurements.
This statement simply assumes that “practice makes perfect”
(or at least that we learn by experience),
which is a reasonable assumption.
