Estimate the median for the given data by drawing ogive :

Class	Frequency
0 - 10	4
10 - 20	9
20 - 30	15
30 - 40	14
40 - 50	8

Cumulative frequency distribution table :

Here, n = 50, which is even.

By formula,

Median = $\dfrac{n}{2}\text{ th term} = \dfrac{50}{2}$ = 25th term.

Steps of construction of ogive :

1. Take 2 cm = 10 units on x-axis.

2. Take 1 cm = 5 units on y-axis.

3. Plot the point (0, 0), as ogive always starts on x-axis representing the lower limit of the first class.

4. Plot the points (10, 4), (20, 13), (30, 28), (40, 42) and (50, 50).

5. Join the points by a free hand curve.

6. Draw a line parallel to x-axis from point A (frequency) = 25, touching the graph at point B. From point B draw a line parallel to y-axis touching x-axis at point C.

From graph, C = 28.

Hence, median = 28.