Question

Calculate the mean given the frequency table

Class
Frequency
0-9
24
10-19
20
20-29
32

Answer 1

~15.55 is the mean.

Explanation:

The class of frequency is given as 0-9, 10-19 and 20-29.

First of all, let us taken middle value of class:

`(0+9)/(2) = 4.5`

`(10+9)/(2) = 14.5`

`(20+9)/(2) = 24.5`

Formula for mean:

`\text{Mean = } (\sum (m * f))/(\sum f)`

where f is the frequency

and m is the mean value calculated in above step (4.5, 14.5 and 24.5)

The frequencies are given as:

4.5 - 24

14.5 - 20

24.5 - 32

Putting the values in above formula:

`Mean = (4.5* 24+14.5* 20 +24.5* 32)/(24+20+32)\\\Rightarrow (108+290+784)/(76)\\\Rightarrow (1182)/(76) \\\Rightarrow 15.55`

Please refer to the attached image that contains the table for calculation of mean.

So, mean = ~15.55