ICSE Guess > ICSE/ISC eBooks > Class X > Maths by Mr. M. P. Keshari

ICSE / ISC eBooks

Example – 1. Find the mean of the following distribution :

Solution :-

Mean = ∑ f x / ∑f = 985/41 = 24.02.

Example – 2. If mean of the following distribution is 7.5, find the missing frequency ‘f’ :

Solution :-

Mean = ∑ f x / ∑ f 

Or,  7.5 = (563 + 7f) / (74 + f)

Or,   555 + 7.5f = 563 + 7f

Or,  0.5f = 8

Or,  f = 16.