Course ratings. The Institute for Statistics Education at Statistics. com asks students to rate a variety of aspects of a course as soon as the student completes it. The Institute is contemplating instituting a recommendation system that would provide students with recommendations for additional courses as soon as they submit their rating for a completed course. Consider the excerpt from student ratings of online statistics courses shown in Table 14.16, and the problem of what to recommend to student E. N. a. First consider a user-based collaborative filter. This requires computing: