Can test prep courses actually help raise LSAT scores? One organization says that the 64 students they tutored achieved an average gain of 10 points when they retook the test. Complete parts a) through c) below. a) Explain why this does not necessarily prove that the test prep course caused the scores to go up. Choose the correct answer below. A. The average gain of 10 points may be due to a few strong outliers. O B. The 64 students may not be representative of the population of all students. O C. The 64 students were not randomly assigned to take the test prep course. There may be confounding variables that are causing the scores to go up. O D. The organization used a randomized experiment. b) Propose a design for an experiment that could test the effectiveness of the test prep course. Choose the correct answer below. A. Randomly assign students into two groups. The first group will take the test prep course and retake the exam; the second group will take the test prep course but not retake the exam. Compare the average gains of the two groups. B. Randomly assign students planning to retake the test to take the test prep course. Compare the average score on the first test to the average score on the second test. O C. Randomly assign students planning to retake the test into two groups. The first group will take the test prep course; the second group will not take the test prep course. Compare the average gains of the two groups. OD. Randomly sample some students planning to retake the test and that are taking the test prep course. Randomly sample some students planning to retake the test and that are not taking the test prep course. Compare the average gains of the two groups. c) Suppose one suspects that the test prep course might be fore helpful for students whose initial scores were low. How would this affect your proposed design? O A. Block the students planning to retake the test by Low, Average, and High scores on the initial test. Within each block, replicate the experimental design described in part b). O B. Avoid selecting students that have low initial scores for random assignment. O C. Students with low initial scores should be assigned not to take the special course; students with other initial scores should be assigned to take the special course. O D. Students with low initial scores should be assigned to take the special course; students with other initial scores should be assigned not to take the special course