Coefficient of Variation

Standard Deviation is an absolute measure — it carries the same unit as the original data — so it cannot, by itself, be used to compare the variability of two series that are in different units or have very different average values. The Coefficient of Variation (C.V.) solves this by expressing the Standard Deviation as a percentage of the mean:

Using C.V. to compare consistency: when comparing two data sets, the series with the smaller C.V. is said to be more consistent (less variable, more stable), and the series with the larger C.V. is said to be less consistent (more variable). This is the standard tool the Gujarat Board Class 11 Statistics syllabus uses for comparing the variability or consistency of two different series — for example, comparing the consistency of runs s …