Find the median of the following data
 

Marks(less than)	No. of students
10	5
20	20
30	45
40	70
50	80
60	88
70	98
80	100

Dear student
 

Class interval	Cf	f
0-10	5	5
10-20	20	15
20-30	45	25
30-40	70	25
40-50	80	10
50-60	88	8
60-70	98	10
70-80	100	2

Median Class = N/2 = 100 / 2 = 50
Median Class = 30-40
Median = l + n/2 -cf / f * h
Median = 30 + 100/2 -45 / 25 * 10
Median = 30 + 50-45/25 * 10
Median = 30 + 5/25 *10
Median = 30 + 1/25 * 10
Median = 30 + 1/5*2
Median = 30.4

Regards