The number of hours of classes attended by students in a semester and the corresponding number of students is tabulated below. Find the coefficient of mean deviation about median.
Number of hours100−120120−140140−160160−180180−200Number of students192830167
0.14
Class IntervalFrequencyCumulative Frequency100−1201919120−1402847140−1603077160−1801693180−2007100
N2=50
Median class is 140-160
M=L+N2−c.ff×h=140+50−4730×20=142
Deviations from the median are tabulated below
X (class midpoint)FD=|X−M|FD110193263813028123361503082401701628448190748336 ∑F=100∑FD=1998
M.D(M)=1998100=19.98
Coefficient of M.D(M)=M.D(M)Median=19.98142=0.14