D A high school math department conducts a study to determine whether a new AP Statistics textbook will lead to higher AP exam scores than the textbook currently in use. Two AP Statistics classes are scheduled, each teacher has 18 students, and it is randomly decided which class will use which book. At the end of the academic year, the 18 students in each class take the AP Statistics exam, and the department notes the scores. (a) Identify the response variable, the treatments, and the experimental units. (b) Was randomization properly used? Explain. (c) Was replication properly used? Explain. (d) Teacher is a confounding variable. Explain