The ‘less than’ cumulative frequency distribution of marks (out of 60) for 40 students is given below:
Upper limit (marks):\;10 \; 20 \; 30 \; 40 \; 50 \; 60
Cumulative frequency: \;6 \; 14 \; 23 \; 31 \; 37 \; 40
Estimate the median marks for the group.
(a) 27.5
(b) 26.7
(c) 25.0
(d) 30.0