Question

The expected value of a random variable can be thought of as a long-run average. True or False

Answer 1

true

in probability theory, a long-run average can be said to follow the law of large numbers.
This theorem describes the result of performing the same experiment a large number of times. According to the law, the average of the results obtained from a large number of trials should be close to the expected value, and will tend to become closer as more trials are performed.

http://en.wikipedia.org/wiki/Law_of_large_numbers