Question

By drawing an ogive, estimate the median for the following frequency distribution: 

Weight (kg)	10 – 15	15 – 20	20 – 25	25 – 30	30 – 35
No. of boys	11	25	12	5	2

Answer 1

Weight (kg)	No. of boys	Cumulative Frequency
10 – 15	11	11
15 – 20	25	36
20 – 25	12	48
25 – 30	5	53
30 – 35	2	55

Number of terms = 55 

∴ Median = `(55 + 1^(th))/2` term

= 28^th term

 
Through mark of 28 on the y-axis, draw a line parallel to x-axis which meets the curve at A. From A, draw a perpendicular to x-axis, which meets x-axis at B. 

The value of B is the median which is 18.4 kg.