Two men each toss a coin. They obtain a "match" if either both coins are heads or both are tails. Suppose the tossing is repeated three times.
a. What is the probability of three matches?
b. What is the probability that all six tosses (three for each man) result in tails?
c. Coin tossing provides a model for many practical experiments. Suppose that the coin tosses represent the answers given by two students for three specific true-false questions on an examination. If the two students gave three matches for answers, would the low probability found in part a suggest collusion?