# [racket] a small programming exercise

On Fri, Oct 15, 2010 at 10:05 AM, Phil Bewig <pbewig at gmail.com> wrote:
>* Not quite.
*>* Random numbers are uniformly distributed, so the first digits of a set of
*>* random numbers should all appear equally.
*>* Benford's Law most often applies to sets of naturally-occurring numbers that
*>* are scale-invariant. Consider the lengths of rivers, as Benford did. It
*>* doesn't matter whether the rivers are measured in miles or kilometers
*>* (scale-invariant). The first digits of the lengths of the rivers will
*>* conform to Benford's Law, as long as the set has enough elements.
*>* Auditors use Benford's Law to find anomalous records. Apply Benford's Law
*>* to a list of the amounts of all checks written by a company in the last
*>* year. If you see too many checks that start with the digits 7, 8, or 9,
*>* there is a clear indication of fraud. The embezzler wrote checks that were
*>* slightly less than $1000, on the theory that small checks would more likely
*>* be ignored. But instead of writing checks for $263 or $347 or $519, he
*>* wrote checks for $838 or $922 to maximize his payout.
*>* There was an external audit of the voting results in last year's Iranian
*>* elections. The audit clearly showed fraud, as there were far too many
*>* precinct tallies that started with the digits 8 or 9.
*
I just love seeing real useful application of seemingly abstract math
concepts... :)