Suppose we flip two coins in which the coins are flipped independently. The coins are fair so
each has probability 1/2 of landing as a head (หัว) and probability 1/2 of landing as a tail (ก้อย).
Let A = 1 if the first coin lands as a head and A = 0 if it lands as a tail. Similarly, let B = 0 if
the second coin lands as a head and B = 1 otherwise.
1.1 What is the expected value of A?
1.2 What is the expected value of B?
1.3 If we define the “score” to be A + B, what are the expected value of the score?