\[Coefficient{\text{ }}of{\text{ }}Variation{\text{ }}CV = \frac{{Standard{\text{ }}deviation{\text{ }}of{\text{ }}x}}{{Average{\text{ }}value{\text{ }}of{\text{ }}x}}\]
\[Coefficient{\text{ }}of{\text{ }}variation{\text{ }}sales = \frac{{Standard{\text{ }}deviation{\text{ }}of{\text{ }}operating{\text{ }}income}}{{Mean{\text{ }}sales}}\]