The teaching effectiveness of 3 teachers were to be compared by obtaining the average scores of 5 exams of 10 students for 3 semesters. Flag question: Question 2 Question 2 3 pts The cases of this study are Group of answer choices 3 teachers 10 students 3 semesters the 15 exams from each studentThe explanatory variable is Group of answer choices 5 exams for each student 5 exams for each student for all 3 semesters average exam score of each student for e for each semester teacher identification code