An engineering professor wants to determine which subject engineering students find most difficult among statistics, physics, and chemistry. She obtains the final exam grades for four students who took all three courses last semester and who were in the same sections of each class. The results are presented in the following table.

a. The professor proposes a randomized complete block design, with the students as the blocks. Give a reason that this is likely not to be appropriate.

b. Describe the features of the data in the preceding table that suggest that the assumptions of the randomized complete block design are violated.

Student 3 78 Course Statistics Physics Chemistry 82 70 83 70 94 75 93 70 82 81 80 3.