RV Coin Machine, Lec 17 on 10/10 ECE302Fall2008sanghavi - Rhea

Set-Up:

• Suppose you have a machine that produces random coins. (Thus, the probability of taking a coin from the machine, tossing it, and getting a 'heads' is a random variable.
• Suppose f_Q(q)= 2q for 0<q<1
• If Q = q then P(H|Q=q) = q

• Below graph:

f_Q(q) vs q

• File:RVCoinMach.JPG ECE302Fall2008sanghavi

Question:

• Suppose you take a coin from the Random Coin Machine and toss is. What is the probability of flipping a heads?

Answer:

• P(H) = $ = \int_{0}^{1}P(H|Q=q) * fQ(q) dq $
  
• = $ = \int_{0}^{1}q^2*q dq $
  
• = 2/3