problem in statistics

may I request assistance on how to go on with this problem. thank you.

Let us consider the three groups of seven student, where each group is subjected to one of the three strategies or method of teaching. Group A was exposed to Exploratory Approach. Group B for cooperative Learning, and Group C for Traditional Method. The grades of the students are presented below. Test if there is a difference in the three methods or strategies of teaching at 5% level of significance.