A person claims to have ESP (extrasensory perception). A coin is tossed 16 times, and each time the person is asked to predict in advance whether the coin will land heads or tails. The person predicts correctly 75% of the time (i.e., on 12 tosses). What is the probability of being correct 12 or more times by pure guessing?
The problem has been solved using a normal approximation to the binomial distribution.