Can someone watch the Digits episode and explain Benford's Law?
en.wikipedia.org
Benford's law, also called the
Newcomb–Benford law, the
law of anomalous numbers, or the
first-digit law, is an observation about the
frequency distribution of
leading digits in many real-life sets of numerical
data. The law states that in many naturally occurring collections of numbers, the leading digit is likely to be small.
[1] In sets that obey the law, the number 1 appears as the leading significant digit about 30% of the time, while 9 appears as the leading significant digit less than 5% of the time. If the digits were distributed uniformly, they would each occur about 11.1% of the time.
[2] Benford's law also makes predictions about the distribution of second digits, third digits, digit combinations, and so on.
The graph to the right shows Benford's law for
base 10, one of infinitely many cases of a generalized law regarding numbers expressed in arbitrary (integer) bases, which rules out the possibility that the phenomenon might be an artifact of the base 10 number system. Further generalizations were published in 1995
[3] including analogous statements for both the
nth leading digit as well as the joint distribution of the leading
n digits, the latter of which leads to a corollary wherein the significant digits are shown to be a
statistically dependent quantity.
It has been shown that this result applies to a wide variety of data sets, including electricity bills, street addresses, stock prices, house prices, population numbers, death rates, lengths of rivers, and
physical and
mathematical constants.
[4] Like other general principles about natural data—for example the fact that many data sets are well approximated by a
normal distribution—there are illustrative examples and explanations that cover many of the cases where Benford's law applies, though there are many other cases where Benford's law applies that resist a simple explanation.
[5] It tends to be most accurate when values are distributed across multiple
orders of magnitude, especially if the process generating the numbers is described by a
power law (which is common in nature).
The law is named after physicist
Frank Benford, who stated it in 1938 in a paper titled "The Law of Anomalous Numbers",
[6] although it had been previously stated by
Simon Newcomb in 1881.
[7][8]
The law is similar in concept, though not identical in distribution, to
Zipf's law.