Question

The class marks of a distribution are as given below:
12, 16, 20, 24, 28, 32, 36.
Determine () the class size (i) the class interval.
​

Answer 1

Given: Classmarks distribution is  12, 16, 20, 24, 28, 32, 36.

To find: The class size and the class interval.

​Solution:

To determine the class size, subtract the consecutive numbers i.e.  

16 - 12 = 4 and

20 -16 = 4

Therefore, the class size is 4 which is obtained by the subtraction of adjacent consecutive numbers in the series.

To determine the class interval, divide the class size value by 2

= 4/2

=2

The value obtained (2) is now subtracted and added to the series  

= series are 12, 16, 20, 24, 28, 32, 36.

Class interval = 12 is subtracted with 2 and added with 2 to obtain the class interval as 10 - 14, similarly, 16 is subtracted with 2 and added with 2 to obtain the class interval 14 - 18.

Hence, the class size is 4 and the class interval is said to be with the difference of 4 which is 10 -14, 14 -18, 18 - 22, 22 -26, 26 - 30, 30 - 34, 34 - 38