# Expected value

#### brainfried78

##### New Member
I can't figure out how to set this up. The compilation of data is boggling my mind. Do i use the 0,1,2,3,4,5,6,7,8,9 to figure my probabilities?

a lottery entitled "Big 4". To win, a player must correctly match 4 digits from a daily lottery in which four digits are selected. Digits are the numbers 0-9, so there are 10 digits. If the payoff for a $100 bet is$10000, what is the expected value of winning? Is it worth it?

Thank you,

#### katxt

##### Member
Here's a start. Think of a raffle with tickets numbered from 0000 to 9999. How much does it cost to buy all the tickets? How much do you win?

#### Buckeye

##### Member
Figure out the sample space of all 4-digit tickets. From there, the probability of winning should be straight-forward. Then the expected value is the sum of x*p(x). x is the payout and p(x) is the probability.

#### brainfried78

##### New Member
Thank you,

this helped me solve my equation.

Last edited:

#### brainfried78

##### New Member
Thank you.
Does that mean that each digit could have 10 possible options? Meaning that it could be 0123? so it would be basically 10x10x10x10 or 10,000 possibilities? So my probability would be 1/10,000?

***i just answered my own question.
thank you for your help

Last edited: