Question

Find the median of the following data.

Class interval	$0-20$	$20-40$	$40-60$	$60-80$	$80-100$
Frequency	$8$	$10$	$12$	$9$	$9$

• A. $45$
• B. $40$
• C. $55$
• D. $50$

Answer 1

The correct option is D $50$

Answer:-

Class interval	Frequency	C. F.
0-20	8	8
20-40	10	18
40-60	12	30
60-80	9	39
80-100	9	48

$\frac{N}{2}=\frac{48}{2}=24$

30 is just greater than 24

$\therefore$Median class $=40-60$

Median = $L+\frac{\frac{N}{2}-C}{f}\times w$

L = lower limit of median class $=40$

C = C. F. of class before median class $=18$

f = frequency of median class $=12$

w = width of median class $=60-40=20$

Median = $40+\frac{24-18}{12}\times 20=40+\frac{6}{12}\times 20=40+10=50$