A group of students are randomly placed in either a traditional AP Stat class or an online-only AP Stat class. Both classes take the same tests. On the first test, the 250 students in the traditional class got an average of 77.5 and a standard deviation of 8.4. The 190 students in the online class scored an average of 79.8 with a standard deviation of 5.1. What is the test statistic for a test with hypotheses