# Expected value: help needed

1. Feb 2, 2010

### Glen Maverick

Expected value: urgent help needed

1. The problem statement, all variables and given/known data

"Spin-and-Win" is under new management. The new management has created the spinner to the right and now charges $1 per spin. (The person spinning wins the amount pointed to by the spinner.) a) What is the expected value for this game? b) What does your answer in part 'a' mean for the owner/manager, if there are 1000 customers who play the game in a week? 2. Relevant equations 3. The attempt at a solution I tried and produced two different solutions, and I don't know which one is right! Trial 1: a) expected value for the player = 0.25*1/2 + 0.50*1/4 + 1*1/4 - 1 = (-)$0.50

b) for the owner, the expected value is (+) $0.50 so , assuming each customer plays once, he will gain 1000*0.50 =$500/wk

Trial 2:

Customers expected winnings = (1/2)*$0.25 + (1/4)*$0.5 + (1/4)*$2 -$1 = - $0.25 This means the owner makes a profit of 25c per customer on average, so$250 in an average week of 1000 customers.
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Could you please check for me? I am so confused!

2. Feb 2, 2010

### Sporkman

Re: Expected value: urgent help needed

Your (a) is wrong - you wrote 1*1/4 but it should be 2*1/4 .

3. Feb 2, 2010

### Glen Maverick

Re: Expected value: urgent help needed

Thank you. I can see that trial 2 is correct.