Answer:Regression toward the mean
Explanation: In terms of psychology, regression towards mean is principle that describes that the chances of gaining extreme or high score in first attempt for any sample in measurement is more which depicts that score is far from average mean. But in second attempt for same sample measurement ,the score will tend to fall towards the average score.
According to the the question, regression towards means is also a factor for the low score apart from coursework. The tendency of score being more away from the average mean was more in first graduate exams.But giving same exams after six months make the score more closer towards the average.