An interesting research question is the effect, if any, that different types of teaching formats have on the grade outcomes of students. To investigate this issue one sample of students' grades was taken from a hybrid class and another sample taken from a standard lecture format class. Both classes were for the same subject. The mean course grade in percent for the 20 hybrid students is 81 with a standard deviation of 5. The mean grades of the 39 students form the standard lecture class was 77 percent with a standard deviation of 5. What is the Test Statistics to test the null hypothesis Ho: 1 = 2 against the alternative hypothesis Ha : l 2?