From Example 1 we can conclude that the probability is 0 that a single roll of a fair die will equal the expected value for a roll of a die (the number of dots facing up is never 3.5). What is the probability that the sum for a single roll of a pair of dice will equal the expected value of the sum for a roll of a pair of dice?

Data from Example 1

What is the expected value (long-run average) of the number of dots facing up for the roll of a single die?