A fair coin is tossed 3 times. If X represents the absolute difference between the number of heads and tails, the expected value E(X) is:

A fair coin is tossed 3 times. If X represents the absolute difference between the number of heads and tails, the expected value E(X) is:

• A. 3/2
• B. 1
• C. 2
• D. 1/2

Answer: A) 3/2

Explanation: Outcomes for (H,T) split: (3,0) or (0,3) happen 2/8 times with diff=3. (2,1) or (1,2) happen 6/8 times with diff=1. E(X) = 3(2/8) + 1(6/8) = 12/8 = 3/2.