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View Full Version : Benfords law?


hermes
19th January 2004, 10:14 PM
Here's a statistical curiosity I picked up somewhere. Some guy in a pub in Darwin noticed the correlation. Long time ago. Don't think it was on this forum.

The story goes that in the 1880s a bored American maths teacher noticed that certain pages of logarhythm tables were worn and grubbied faster than others. Over years of students he did stats on this and honed it down to a formula. Some tables are used more commonly than others.

No one took any notice until the 1930s when a physicist named Benford found the same maths in number frequency. He collected over 20,000 numbers from various sources like drainage logs and old magazines, noting whatever numbers were used. He found that the #1 is the first digit in 30% of all numbers used in his samples. #2 was 18% etc. This was constant.

You can check this by looking at all the numbers visible in your room right now. About 30% of them will be or begin with the digit one. (Its 11:10 and my printer is an ultra-crappy z12, for instance.) The universe, or the human environment, is stacked that way.

Now these proportions correlate uncannily, not with TAB numbers but with first, second, third favourites winning. Faves win about 30% of the time, second faves about 18% of the time and so on, very, very near to Benford's constant.

Another useless fact from

Hermes.

Lenny
19th January 2004, 10:49 PM
Very interesting, Hermes. Do you know the name of the maths teacher you mentioned? Where did you pick up this interesting piece of information?

Cheers

~Lenny

hermes
20th January 2004, 12:14 AM
I got this from an ultra-reliable source - some character on an online punting forum. Its been in my files. Found it today.

I don't know the name of the maths teacher but whoever he was he lost out because Benford's name is given to this phenomenon. A bit like Tesla and Edison.

It is an interesting correlation. The online source used Don Begg's 'Walk Away a Winner', p. 25 for the favourites stats. Begg has them:

1st Fave = 32.3%
2nd Fave = 18.3%
3rd Fave = 12.4#
Fourth Fave = 11.5%

This compares to Benford's results:

Digit 1 = 30.1%
Digit 2 = 17.6%
Digit 3 = 12.5%
Digit 4 = 9.7%

A striking correlation.

Hermes

darkydog2002
20th January 2004, 07:38 AM
AH.My brains ticking over.
Fav must be in tab 1
2nd fav= tab 2
3rd fav =tab 3
4th fav = tab 4.

Another useless illogical system???
Cheers.
Darky.

crash
20th January 2004, 07:54 AM
Benford's Law: The audit technology is now known as Digital Analysis [ DA ] . It tests for abnormalities in the digital patterns and abnormal number duplication in Corporate data.

...and every morning the Sun rises in the East and sets in the West, BUT one day it won't and most people who get shot are wearing green clothes !!!

more useless info. from me.

Cheers.


<font size=-1>[ This Message was edited by: crash on 2004-01-20 09:36 ]</font>

CosMos
20th January 2004, 11:05 AM
Hi guys, first time I have posted here but enjoy your banter.

Link about Benford's Law that explains things a little more fully.

http://www.intuitor.com/statistics/Benford's%20Law.html

hermes
20th January 2004, 01:25 PM
Thanx for the link CosMos. In that link they are using Benford's Law to spot tax fraud it seems. But who has noticed that Benford's proportions give us much the same as the win rates of favourites in horse races?

Admittedly useless

Hermes

kenchar
20th January 2004, 05:01 PM
CosMos,

Interesting site.

I bet if Dr Pan----- goe's there HE won't need viagra :lol:

Keep Smiling :smile:

Lenny
21st January 2004, 01:03 AM
Hi all,

Hermes: You're right about Tesla - he got screwed. An amazing genius we never knew - probably because he developed a method for the free long-distance transmission of power.
* As for the Benford correlation - Very interesting!!!
* BTW the maths teacher that lost out to Benford was Dr. Theodore P. Hill from the Georgia Institute of Technology.

Cosmos: Nice link.

DarkyDog: Now that idea is potentially interesting!

Crash: Pacino says in "meet the family" that intelligent people wear green (psychological fact?) but if true, might prove that no one likes a smart ass :razz:

~Lenny


<font size=-1>[ This Message was edited by: Lenny on 2004-01-21 02:25 ]</font>

crash
21st January 2004, 06:00 AM
Soldiers wearing green fatigues are the most regularly shot people Lenny. But your right about the other, considering the common denominator principle, dumb will always be more popular !

Cheers.





<font size=-1>[ This Message was edited by: crash on 2004-01-21 07:19 ]</font>