Reply to: Benford's law

[scooterscot]

Random data set from clientCo

First Digit           Count 	Percentage
0			196	0%
1			186550	31%
2			104339	18%
3			73074	12%
4			54788	9%
5			47192	8%
6			36954	6%
7			35722	6%
8			28370	5%
9			26546	4%

Creepy.

[BrilloPad]

Any maths to explain why car numbers plates have a grossly disproportionate numbers of Xx, Ys, Zs, Vs, Js and Ks ????

I thought I would try and make myself less bad tempered while driving (slow drivers, tractors, cyclists!) by trying and make words and phrases out of number plates, but very difficult when they are nearly all XJC or KXV or ZYF etc.

MF broke the mould with that. He has CU*T 1.

[xoggoth]

Any maths to explain why car numbers plates have a grossly disproportionate numbers of Xx, Ys, Zs, Vs, Js and Ks ????

I thought I would try and make myself less bad tempered while driving (slow drivers, tractors, cyclists!) by trying and make words and phrases out of number plates, but very difficult when they are nearly all XJC or KXV or ZYF etc.

[mudskipper]

Random data set from clientCo

First Digit           Count 	Percentage
0			196	0%
1			186550	31%
2			104339	18%
3			73074	12%
4			54788	9%
5			47192	8%
6			36954	6%
7			35722	6%
8			28370	5%
9			26546	4%

[Contreras]

So, ignoring base 10 numbers, I'd see a similar pattern in octave and hexadecimal counting systems?

Please no don't make me do that.

[scooterscot]

Logarithms. That's what causes it.

So, ignoring base 10 numbers, I'd see a similar pattern in octave and hexadecimal counting systems?

[NotAllThere]

...What's going on?

Logarithms. That's what causes it.

[northernladuk]

And for all the other thick bastards like me that don't have a clue what's happening here...

Benford's law - Wikipedia, the free encyclopedia

Interesting comment in there to help fend off HMRC for the less scrupulous of you though..

Accounting fraud detection[edit]

In 1972, Hal Varian suggested that the law could be used to detect possible fraud in lists of socio-economic data submitted in support of public planning decisions. Based on the plausible assumption that people who make up figures tend to distribute their digits fairly uniformly, a simple comparison of first-digit frequency distribution from the data with the expected distribution according to Benford's Law ought to show up any anomalous results.[14] Following this idea, Mark Nigrini showed that Benford's Law could be used in forensic accounting and auditing as an indicator of accounting and expenses fraud.[15] In practice, applications of Benford's Law for fraud detection routinely use more than the first digit.[15]

[MicrosoftBob]

It works after the decimal point as well. Many years ago an American programmer made a lot of money by realising the actual mid-point for rounding was not 50 cents but roughly 33 cents. He wrote a programme that reported the rounding based on 0,5 but calculated it at 0.3 and put the balance in his own account.

Was that before or after Office Space ?

[Contreras]

Perhaps there's a fraud in progress.

I was just thinking that too.

[OwlHoot]

It's smeging disturbing.

I've tried testing some random data sets from bank statements to historical values, nearly every time the leading digit '1' comes up 30% of the time.

What's going on?

Could it be that your annual salary is £15000, and your monthly pay packet is £1005 ?

[scooterscot]

For business/personal current account transactions it's nearer 40% here!

Digit		Business	Personal	Predicted
1		38.7%		42.9%		30.1%
2		16.7%		20.0%		17.6%
3		8.9%		10.9%		12.5%
4		8.9%		7.0%		9.7%
5		9.5%		6.6%		7.9%
6		4.2%		2.1%		6.7%
7		5.4%		2.9%		5.8%
8		2.4%		3.8%		5.1%
9		5.4%		3.8%		4.6%

Sample size	336		1535

Perhaps there's a fraud in progress.

[Contreras]

It's smeging disturbing.

I've tried testing some random data sets from bank statements to historical values, nearly every time the leading digit '1' comes up 30% of the time.

What's going on?

For business/personal current account transactions it's nearer 40% here!

Digit		Business	Personal	Predicted
1		38.7%		42.9%		30.1%
2		16.7%		20.0%		17.6%
3		8.9%		10.9%		12.5%
4		8.9%		7.0%		9.7%
5		9.5%		6.6%		7.9%
6		4.2%		2.1%		6.7%
7		5.4%		2.9%		5.8%
8		2.4%		3.8%		5.1%
9		5.4%		3.8%		4.6%

Sample size	336		1535

[malvolio]

That was Superman 3 you're thinking of.

In 1968...? Don't think so.

[barrydidit]

It works after the decimal point as well. Many years ago an American programmer made a lot of money by realising the actual mid-point for rounding was not 50 cents but roughly 33 cents. He wrote a programme that reported the rounding based on 0,5 but calculated it at 0.3 and put the balance in his own account.

That was Superman 3 you're thinking of.