Question

The mean of $100$ observations is $18.4$ and sum of squares of deviations from mean is $1444$, the Co-efficient of variation is _______.

• A. $30.6$
• B. $35.6$
• C. $20.6$
• D. $10.6$

Answer 1

The correct option is C $20.6$

Standard deviation is the square root of the arithmetic mean of the squares of the deviations measured from the arithmetic mean of the data.

Standard deviation = { (sum of the squares of the observations/ number of observations ) – (sum of observations/ number of observations ) } ^½

= { (1444) –(18.4) } ^½

= (1425.6) ^½

= 37.75

Coefficient of variation is the coefficient of dispersion based on the standard deviation of the statistical series.

Coefficient of variation = ( standard deviation / mean )x 100

= ( 37.75/ 18.4)x100

= 20.51