Question

For a series the value of mean deviation is 15.The most likely value of its quartile deviation is

• A. 12.5
• B. 11.6
• C. 13
• D. 9.7

Answer 1

The correct option is A 12.5

use: M.D.$=\frac{4}{4}\sigma ,Q.D=\frac{2}{3}\sigma$ $\Rightarrow \frac{M.D.}{Q.D}=\frac{6}{5}\Rightarrow Q.D.=\frac{5}{6}(M.D.)$
$MD=\frac{4}{5}\times \sigma ,QD=\frac{2}{3}\times \sigma ,\frac{MD}{QD}=\frac{6}{5},QD=\frac{5\times 15}{6}=12.5$