The expected value or expectation is the (weighted) average of all the possible outcomes of an event, weighed by their probability. For example, when you roll a die, the expected value is (1+2+3+4+5+6)/6 = 3.5.

(Since a die doesn’t even have a face that says 3.5, this illustrates that very often, the “expected value” isn’t a value you actually expect.)

Anyone objects to deleting this page? There seems to be no significance to it, it’s even not linked from anywhere. --Vladimir Nesov 23:03, 8 July 2009 (UTC)

Video to demonstrate how to NOT think about expected value

George Gervin (NBA Legend) says that the 3-point shot is the worst shot in basketball. His argument is basically that 3-point percentages are almost always lower than 2-point percentages. He seems to not give any weight to the fact that 3-point shots provide you with one extra point...

Perhaps the example should include probabilities

The example with the 6-sided die doesn’t explicitly show how probabilities are part of the calculation. Perhaps the example should do this.

Anyone objects to deleting this page? There seems to be no significance to it, it’s even not linked from anywhere. --Vladimir Nesov 23:03, 8 July 2009 (UTC)

## Video to demonstrate how to NOT think about expected value

http://youtu.be/kuXIpxoMYtc?t=20s

George Gervin (NBA Legend) says that the 3-point shot is the worst shot in basketball. His argument is basically that 3-point percentages are almost always lower than 2-point percentages. He seems to not give any weight to the fact that 3-point shots provide you with one extra point...

## Perhaps the example should include probabilities

The example with the 6-sided die doesn’t explicitly show how probabilities are part of the calculation. Perhaps the example should do this.