Question

20. Roma knows about how to find the arithmetic mean from the given data which is 53) but she has
confused how to find the unknown term so she asked to her father to help for this type of problem.
60 - 80
80 - 100
Class
Frequency
0 - 20
12
20 - 40
15
40 - 60
32
I
​

Answer 1

K = 28

Step-by-step explanation:

Given class intervals and frequency, let's find the mid-point of each class interval x and multiply it with frequency to get fx.

Arithmetic Mean = Sum of fx / sum of f = (3340 + 70 k) / (72 + k) = 53

(3340 + 70 k) = 53 (72 + k)  

3340 + 70k = 53k + 3816

 17k = 476

k = 476 / 17

Therefore k = 28. Hence solved.