Question

The mean of the following frequency distribution of 125 observations is 22.12 :
Class 0-4 5-9 10-14 15-19 20-24 25-29 30-34 35-39 40-44
Frequency 3 8 12 i 35 21 12 6 1 2
Find the missing frequencies​

Answer 1

Answer:

I hope this would help you

Answer 2

The missing frequencies are 20 and 18.

Given :

The mean of 125 observations is 22.12

To find :

The missing frequencies.

Solution:

From the table,

$f_1 = 87 + f_1 + f_2\\\\125 = 87 + f_1 + f_2 \\\\f_1 + f_2 = 38$

Now mean,

$x = a + ( f_2 m_1/f)*h\\\\22.12 = 17 + (74+3f_2)/125*5\\\\5.12 = 74*3f_2/25\\\\5.12 * 25 = 74 + 3f_2\\\\54=3f_2\\ \\f_2 = 18$

Then from

$f_1 + f_2 =38,\\\\f_1 = 20$

Thus, the missing frequencies are 20 and 18.

#SPJ2