# Thread: Expected Value of Dice

1. ## Expected Value of Dice

Roll two dice and find E(X) and the variance of X if:

• X is the product of the two dice
• X is the larger of the two dice

For b, I have

X=1 then E(X) = 0/36
X=2 then E(X) = 2/36
X=3 then E(X) = 4/36
X=4 then E(X) = 6/36
X=5 then E(X) = 8/36
X=6 then E(X) = 10/36

any help?

2. Originally Posted by asept
Roll two dice and find E(X) and the variance of X if:

• X is the product of the two dice
• X is the larger of the two dice

For b, I have
X=1 then P(X) = 0/36
X=2 then P(X) = 2/36
X=3 then P(X) = 4/36
X=4 then P(X) = 6/36
X=5 then P(X) = 8/36
X=6 then P(X) = 10/36
I made corrections in your notation in red above.
Those should be probabilities: P(X).
Expection is $E(X) = \sum\limits_{x = 1}^6 {xP(x)}$.

For the first part your outcomes 1,2,3,4,...,25,30,36.