# Find the mean deviation about the median for the following data :

$\begin{array}{1 1}(A)\;10.34 \\(B)\;3\\(C)\;2\\(D)\;7\end{array}$

Step 1:
It is a continuous data.
So median can be calculated by
median $=l+\large\frac{N/2-C}{f}$$\times h Step 2 : \large\frac{N}{2}=\frac{50}{2}$$=25$
=> $C= 14,f=14,l=20,h=10$
Step 3:
Median $M= l+\large\frac{N/2-c}{f} $$\times h \qquad= 20+ \large\frac{11 \times 10}{ 14} \qquad= 20+ 7.86 = 27.86 Step 4: Mean deviation about the mean = \large\frac{\sum f_i |x_i -\bar{x}|}{\sum f_i} \large\frac{517.16}{50}$$=10.34$
Hence A is the correct answer.