Coke and Pepsi are the two most popular colas on the market. Do consumers prefer either one of the two brands of cola over the other? We conduct a matched pairs experiment as follows: 20 volunteers participate in a blind taste test. Each volunteer tastes both Coke and Pepsi (in random order) and scores the taste of each cola on a scale from 0 to 100. Some information that may be helpful is shown in the table below: Scores for Coke mean = 78 std. dev. = 27 Scores for Pepsi mean = 83 std. dev. = 24 Difference (d = Coke - Pepsi) mean = -5 std. dev. = 13 What are the hypotheses for the appropriate test of significance?