Question

Find the mean deviation about the mean of the following data:
$15,17,10,13,7,18,9,6,14,11$.

• A. $3.1$
• B. $3.2$
• C. $3.3$
• D. $3.4$

Answer 1

Answer: (D)

$3.4$

Let the mean of data be $u=\frac{\sum x_i}{n}=\frac{120}{10}=12$
Calculating the deviation : $|x_i-u|$ we get,
$3,5,-2,1,5,6,3,6,2,1$.
$\therefore M.D\left(u\right)=\frac{\sum |x_i-u|}{n}=\frac{34}{10}=3.4$
Thus, $M.D\left(u\right)=3.4$.
Ans- Option $D$