Four fair dice are rolled Find the expected total of the rol

Four fair dice are rolled. Find the expected total of the rolls.

Solution

Note that each side of a die has equal probability of showing up, 1/6.

For a single die,

E(x) = 1(1/6) + 2(1/6) +3(1/6) + 4(1/6) + 5(1/6) + 6(1/6)

= 3.5

Thus, for 4 dice,

E(4x) = 4E(x) = 4*3.5 = 14 [ANSWER]