4.5 In football, the offensive coach may call a running play or a passing play. Of course, the defense can either defend against a run or defend against a pass. The defense “wins” if it defends against the correct type of play, and the offense “wins” if the defense is not defending against the play that it runs. Offensive coaches are always told to mix up their plays. Interpret this advice in terms of a mixed strategy, and explain why using any sort of nonrandom strategy is a bad idea.