Question

If $n=10,\overline{x}=12$ and $\sum x^2=1530$, then calculate the coefficient of variation.

• A. $20$
• B. $25$
• C. $30$
• D. $35$

Answer 1

The correct option is B $25$

$\sigma =\sqrt{\frac{\sum x^2}{n}-{\left(\frac{\sum x}{n}\right)}^2}$

$=\sqrt{\frac{1530}{10}-(12{)}^2}$

$=\sqrt{153-144}$

$=\sqrt{9}$

$=3$

Coefficient of variation $=\frac{\sigma }{\overline{x}}\times 100$

$=\frac{3}{12}\times 100$

$=\frac{1}{4}\times 100$

$=25$