A fair die is thrown. What is the expected value of its score?

Explanation

1. 01

   Each face has probability $\frac{1}{6}$: $E(X) = \frac{1 + 2 + 3 + 4 + 5 + 6}{6} = \frac{21}{6}$.

2. 02

   $= 3.5$, a value the die never shows: an expectation is a long-run average.