Mr. Benford

Abstract

Would you like to win a bet? Let’s see if you can manage to guess the first digit of a number or at least whether that number is less than 4. Tell somebody to think of everyday-life numbers, such as the street number of a house or the amount of money they have in their checking account, or a percentage rate they commonly use such as a mortgage interest rate, or, perhaps, a physical or mathematical constant such as pi. If your bet is that this number begins with 1, 2, or 3, you will be right more than half the time, in fact, you will be right 60.2% of the time. Your betting partner will no doubt be surprised by your success rate, for at first sight there is no reason at all for the laws of chance to produce such a result.