Random Patterns
Have you ever
looked at what is supposed to be a random set of numbers and think some numbers
appear more so than others.
It turns out that
in a given list of numbers representing anything from electricity bills, street addresses, stock prices,
population numbers, death rates, lengths of rivers bout 30% of the numbers
will begin with the digit 1. And less will begin with 2, even less with 3, and
so on, until only one number in twenty will begin with a 9. The bigger the data
set, and the more orders of magnitude it spans, the more strongly this pattern
emerges.
The mathematical
formula describing this digit distribution is called Benford's law, and its
explanation, only discovered in 1998, has to do with logarithms and power laws.
Simply put, it says that the values of measurements are more likely to start
with the digit 1 than with 9 because there are typically more small things than
there are big things.
Benford's law has
been used in fraud cases to prove that a data set that doesn't conform
to the law must be fraudulent. After all, when forging numbers, most people
naturally assume that they should give all digits equal play to make the data
seem random.
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