While he was a prisoner of war during World War II, John Kerrich tossed a coin times. He gotheads. If the coin is perfectly balanced, the probability of a head is .
(a) Find the mean and the standard deviation of the number of heads in tosses, assuming the coin is perfectly balanced.
(b) Explain why the Normal approximation is appropriate for calculating probabilities involving the number of heads in tosses.
(c) Is there reason to think that Kerrich’s coin was not balanced? To answer this question, use a Normal distribution to estimate the probability that tossing a balanced coin times would give a count of heads at least this far from (that is, at least heads or no more than heads