Alex flips a fair coin 20 times. Bert spins a fair coin 21
times. Bert wins if he gets more heads than Alex, else Alex wins.
Note that Alex wins if there is a tie. What is the probability that
Bert wins?
A recent study at (Yale? Harvard? some East Coast college) confirmed that, in a controlled environment, with a machine that can flip a nickel the exact same way every time, heads came up 50.1% of the time and tails 49.9%.
Don't worry, though. At most coin-flipping places the grass screws up all the figures, so it's not significant enough a difference to matter.
Probability under a microscope
