[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... :)