We are given the table which shows age distribution of the persons in a particular regions;
Year No. of persons (f) Cumulative frequency (cf)
10 200 200
20 500 700
30 900 1600
40 1200 2800
50 1400 4200
60 1500 5700
70 1550 7250
80 1560 8810
∑f = 8810
Firstly we will find = = 1101.25 .
Now in cf table we will look for the value which just greater than or equal to 1101.25 which comes out to be 1600.
Now corresponding to this cf value the age is 30.
Therefore the median age comes out to be 30 years