Frequency Distribution

[masumeh]

Hi all. I have a question, that is very important for me!
It is written in book "basic statistics for business and economics" for organizing data into a frequency distribution:
step 1: Decide on the number of classes. The goal is to use just enough groupings or classes to reveal the shape of the distribution. Some judgment is needed here. A useful recipe to determine the number of classes (k) is the "2 to the k rule". This guide suggests you select the smallest number (k) for the number of classes such that 2^k (in words, 2 raised to the power of k) is greater than the number of observations (n). [n<=2^k]

I want to know, how can I prove this formula?
Please Help!

 

[DrPhil]

Hi all. I have a question, that is very important for me!
It is written in book "basic statistics for business and economics" for organizing data into a frequency distribution:
step 1: Decide on the number of classes. The goal is to use just enough groupings or classes to reveal the shape of the distribution. Some judgment is needed here. A useful recipe to determine the number of classes (k) is the "2 to the k rule". This guide suggests you select the smallest number (k) for the number of classes such that 2^k (in words, 2 raised to the power of k) is greater than the number of observations (n). [n<=2^k]

I want to know, how can I prove this formula?
Please Help!

You can't "prove" it because there is no unique way to choose class boundaries. It is a recipe, and can give a you a suggestion for k.

Another recipe (from physics instead of from business) is that there must be at least 5 bins (preferably 10 bins) between the points where the frequency drops to half of its maximum, and no bin should have fewer than 10 data.