Select a rst-year college student at random and ask what his or her academic rank was in high school. Here are the probabilities, based on proportions from a large sample survey of rst-year students: Rank Top 20% Second 20% Third 20% Fourth 20% Lowest 20% Probability 0.41 0.23 0.29 0.06 0.01 (a) What is the sum of these probabilities