Question 20 of 36 2 Points Dr. Grey teaches General Surgery, and she is interested in measuring her students' knowledge of the subject. In order to do so, she gave the same 50- item test to all four of her classes. Use this information to answer items 16-20. Class A Class B Class C Class D 30 25 30 20 mean 315 30 43 22 median 31 25 45 25 mode 30 20 47 30 Imagine that Dr, Grey actually made a mistake grading one student's test paper in class D. That student's score should be decreased by 20 points. What effect will this have on the mean score in class D? A. it will be decreased by 1 point B, it will remain unchanged O C. It will decrease, but more Information is needed to determine by how much. D, it will be decreased by 20 points Reset Selection