Question

The following distribution shows the daily pocket allowance of children of a locality. If the mean pocket allowance is ₹ 18 , find the missing frequency f.

Daily pocket allowance (in ₹)	11 – 13	13 – 15	15 – 17	17 – 19	19 - 21	21 – 23	23 – 25
Number of children	7	6	9	13	f	5	4

Answer 1

The given data is shown as follows:

The mean of the given data is given by,

⇒ 18 = \(\frac{750+20f}{44+f}\)

⇒ 18 (44 + f) = 752 + 20f 

⇒ 792 + 18f = 752 + 20f 

⇒ 20f – 18f = 792 – 752 

⇒ 2f = 40 

⇒ f = 20 

Hence, the value of f is 20.