Page 38 - Pharmaceutical Analytical Chemistry III

Measures of Dispersion

Three terms are widely used to describe the

dispersion (precision) of a set of replicate

data:

standard deviation, variance, and coefficient

of variation.
These three are functions of how much an

individual result xi differs from the mean,
called the deviation from the mean di.

Note that deviations from the
mean are calculated without
regard to sign.