Saturday, 6 July 2013

Benford's Law Update

The last Benford update was almost two years ago, and since the topic came up, it seemed as good a time as any to update the numbers.

After 2,520 active days on Betfair since 1/1/2006 (what a life), the numbers look like this:

The numbers as of 2009 and 2011 are left in as a reference, and not too much has changed in two years. The 1 has gone up a little, and now occurs slightly more often than it should, but the 2 shows up slightly less than expected. No digit is more than 1% off - and overall they match pretty closely.

The scariest part of this exercise was probably that I have totalled just 222 days of being completely idle in seven and a half years, although activity varies from one punt to several hours of trading.

If anyone else wants to try this, I feel very sorry for you, but Excel does makes it easy, and heaven forbid you have a few negatives in your spreadsheet, the below formula accounts for that and generates the Benford number for you.

E29 is the cell you are targeting:

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