A popular theory is that presidential candidates have an advantage if they are taller than their main opponents. Listed are heights (in centimeters) of randomly selected presidents along with the heights of their main opponents. Complete parts (a) and (b) below. Height (cm) of President 178 175 178 183 197 170 Height (cm) of Main Opponent 166 187 174 175 184 174 pairs of data, where each individual difference d is defined as the president's height minus their main opponent's height. What are the null and alternative hypotheses for the hypothesis test? Ho Hd = 0 cm H: Hd > 0 cm (Type integers or decimals. Do not round.) Identify the test statistic. t = (Round to two decimal places as needed.)