Ashish and Matt walk us through 3 expected value problems in our first online video series! Checkout MATH115.COM for more video content. Below is a link to my expected value page which also includes a printable problems worksheet that goes with these videos.
http://math115.com/2011/02/expected-value/
The second way you looked at the problem you didn't include the "0" winning outcome - the reason you want that outcome is that when you look at the probabilities you now know that this sum is 1 (otherwise if you were checking your work you may be trying to figure out why the probabilities did not add to 1).
fothpima 5 months ago