The table b

Where N = total samples

C.F = Cumulative frequency of class preceding median class

f = Frequency of the median class

h = width of the Class interval

l = Lower limit of median class

(Note: The median class is the class under which observation falls)

, which falls in (10 – 15) which is now the median class

Putting necessary values in the formulae

= 10 + 3.421

= 13.421 thousand rupees