Question

Find unknown frequency in the following data of N = 100 and median = 32

Class-interval	0-10	10-20	20-30	30-40	40-50	50-60	Total
Frequency	10	f1	25	30	f2	10	100

Answer 1

Let f₁ and f₂ are unknown frequency, then

Thus, 75 + f₁ + f₂ = 100

f₁ + f₂ = 100 – 75 = 25

Given: Median = 32

So, median class is 30 – 40.

Thus, l = 30, h = 10, f = 30, C = 35 + f₁

15 – f₁ = 6

f₁ = 15 – 6 = 9

From eqn.(i), f₂ = 16

Thus, f₁ = 9, f₂ = 16