Find the median for the following data.

This is a grouped frequency distribution, in which median is calculated as follows.

We have the following table:

Here, we get total frequency, N = 30. So,

Since, N/2 = 15. Mark a cumulative frequency which is just greater than 15.

Here, it is 17. So, median class would be 15 – 20.

Median is given by

Where, l = lower limit of the median class = 15

N/2 = 15 (as calculated above)

m = cumulative frequency of the class preceding the median class = 7

f = frequency of the median class = 10

c = width of the median class = 5

Putting all these values in the formula, we get

⇒

⇒ Median = 15 + 4 = 19

Thus, median is 19.