Calculate the median of the following frequency distribution:

Weight (in nearest kg)	Number of students
45	8
46	5
48	6
50	9
52	7
54	4
55	2

Cumulative frequency distribution table :

Here number of observations, n = 41, which is odd.

By formula,

$\Rightarrow \text{Median} = \dfrac{41 + 1}{2} \text{th} \text{ observation} \\[1em] \Rightarrow \text{Median} = \dfrac{42}{2} \text{th} \text{ observation} \\[1em] \Rightarrow \text{Median} = 21 \text{th} \text{ observation} \\[1em] \Rightarrow \text{Median} = \text{Weight of 21 st student}$

From the above table, weight of each student from 20th to 28th are 50.

∴ Weight of 21st student = 50.

Hence, median weight = 50 kg.