Table shows the marks of 130 students of class 10th.

Median of given data is:

Candidate marks	20-30	30-40	40-50	50-60	60-70	70-80
Number of candidates	0	4	18	60	33	15

  

Formula used: 

Where the median class is the class interval whose cumulative frequency ≥ N/2.

N = sum of frequencies, L = lower limit of the median class,

f = frequency of median class, h = width of the class 

C = cumulative frequency of the class just preceding the median class.
Calculation:

We can see that, the sum of frequency

N = 130

N/2 = 65

Hence, 50 - 60 will be the median class, where

L = 50, f = 60, h = 10 and c = 22

\(Median = L + \frac{\frac{N}{2}\ -\ C}{f}\times h\)

\(⇒ Median = 50 + \frac{\frac{130}{2}\ -\ 22}{60}\times 10\)

⇒ Median = 57.16

∴ The median of the data is 57.16