Some of the guidelines given for preparing Frequency distribution for grouped data or "Grouped Frequency Distribution" are given below. I have some doubts regarding the same

  1. All classes or groups should have the same interval. So a class should have a range of say 130-139, 140-149 and so on. Or a range of 500-599, 600-699 and so on.
  2. The lower boundary of each class or group should be a multiple of the class or group interval. Taking the same example below, the first set of class is a multiple of 10 (i.e. 130-139, 140-149 and so on) while the second set of class is a multiple of 100 (i.e. 500-599, 600-699)

Regarding these I have the following queries Firstly why should the interval of a class be uniform along the entire class/groups. Will it not be helpfull to have classes which are half of the interval? For example we have a class/group as 130-139, 140-144, 145-149, 150-159 and so on. It is possible that with this varying group we might avoid over representation of a particular class thus avoid the bias that comes from collecting a sample from a large population.

Secondly why is it recommended that the lower boundary of the class be a multiple of the interval? Taking the same example given above, maybe in certain conditions it may make sense to have a class of say 135-144, 145-154, 155-164 and so on.

Anybody who can shed light on this would be appreciated.


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.