# Finding expected value

• Jan 4th 2012, 07:14 AM
paris
Finding expected value
Can anyone help me to solve part C of this question. I got stuck and really don't know how to find the expected value of the price.

Thank you
• Jan 4th 2012, 07:43 AM
Ridley
Re: urgent help-expected value
Do you know the definition of EV (expected value)? The best way to deal with this is to say that total price for the breakfast is $Z=X+Y$ where X is the cost of the sandwich and Y is the cost of the drink. Then you can calculate the EV of the whole meal as follows: $E(Z)=E(X+Y)=E(X)+E(Y)$

For Y you have:
$P(Y=0)=2/3$
$P(Y=2)=1/3$

$E(Y)=0*2/3 + 2 * 1/3 = 2/3$
• Jan 4th 2012, 07:48 AM
Duke
Re: urgent help-expected value
1/9(12+12+14+14+14+16+15+15+17)=43/3
• Jan 4th 2012, 07:49 AM
Ridley
Re: urgent help-expected value
This is obviously homework, so you shouldn't provide the entire solution.
• Jan 4th 2012, 07:57 AM
paris
Re: urgent help-expected value
This is not my homework. This is my exam question which i can't do it.
So which one is the right solution, Duke or you?
I don't understand expected value because my teacher never teach us about it.
• Jan 4th 2012, 08:08 AM
Ridley
Re: urgent help-expected value
Both solutions lead to the same answer.