Shortly after being hired, eight sales trainees participated in a role playing exercise where they were rated

Question:

Shortly after being hired, eight sales trainees participated in a role playing exercise where they were rated on a scale of 1-10 on their ability to close a sale. After one week of training, the same eight sales trainees participated in the same role playing exercise and their closing skills were evaluated using the same scale of 1-10.
Review the following scores. Is there a difference between the pre-training and post-training rating scores? What effect, if any, did the training have on the trainees? Explain.