The grade distribution for the midterm in your History class with 20 students is given below. Which of the following statements below must be correct? History Grades N=20 9 8 7 6 6 5 4 3 2 61-70 71-80 81-90 91-100 The class average (mean) for this exam is 82 The highest possible class average (mean) for this exam is 90 At least one student got a 100 The lowest grade received by a student is 61 The lowest possible class average (mean) for this exam is 77.5