A test is given and the average (_X) score out of 100 was only a 53.1, with a SD (_X) of 8.9.Assuming the grades followed a normal distribution, use the Z table or Excel and formulas to find the dividing line (test scores) between the A's, B's, C's, D's, and E's.Starting from the top, the teacher will give the highest 15% A's, the next 10% B's, the next 30% C's, the next 25% D's, and the bottom 20% will receive E's.