I have two coins, one fair, and one unfair which shows heads ¾ of the time. I choose a coin at random and flip it 10 times. How many heads do I expect to see? Solve via conditional expectation.
Expected number of heads, given that the coin is fair, E(X | fair) = 10x0.5 = 5
Expected number of heads, given that the coin is unfair, E(X | unfair) = 10x3/4 = 7.5
Expected number of heads = 0.5x5 + 0.5x0.75
= 6.25
I have two coins, one fair, and one unfair which shows heads ¾ of the time....
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