Question

Explain standard deviation with its merits and demerits

Answer 1

Merits

It is rigidly defined and free from any ambiguity.
Its calculation is based on all the observations of a series and it cannot be correctly calculated ignoring any item of a series.
It strictly follows the algebraic principles, and it never ignores the + and – signs like the mean deviation.
It is capable of further algebraic treatment as it has a lot of algebraic properties.
It is used as a formidable instrument in making higher statistical analysis viz.: correlation, skewness, regression and sample studies, etc.

Demerits
It is not understood by a common man.Its calculation is difficult as it involves many mathematical models and processes.
It is affected very much by the extreme values of a series in as much as the squares of deviations of big items proportionately bigger than the squares of the smaller items.
It cannot be used for comparing the dispersion of two, or more series given in different units.

Answer 2

Merits and demerits of standard deviation are it is rigidly defined and free from any ambiguity, it is not understood by a common man.