Question

Look at the frequency distribution table given below:

Class interval	35 – 45	45 – 55	55 – 65	65 – 75
Frequency	8	12	20	10

The median of the above distribution is 

(a) 56.5 

(b) 57.5 

(c) 58.5 

(d) 59

Answer 1

Correct answer is (b) 57.5

Here, N = 50 

⇒ N/2 = 25, which lies in the class interval of 55 – 65. 

Now, cf = 55, f = 20 and l = 50

∴ Median = l + \(\{h\times\cfrac{(\frac{N}{2}-cf)}f\}\)

= 50 + \(\frac{65+55}{20}\) × (25 – 20) 

= 57.5