Calculate mean deviation using median and coefficient of mean deviation :
Class Intervals5−1515−2525−3535−4545−55Frequency54542
N2=202=10th item, Median class is 25 - 35
M=l1+N2−c.ff×i=25+10−95×10=25+2=27
M.DM=∑f|D|N=22620=11.3, Coefficient of M.DM=M.DMM=11.327=0.4185