[This exercise requires a computer program to carry out the multiple regression computa- tions.] At the end of classes, professors are rated by their students on a scale from 1 (poor) to 5 (excellent). Students are also asked what course grades they expect, and these are coded as A = 4, B = 3, and so on. In the table we show, for a random sample of twenty classes, ratings of professors, average expected grades, and the numbers of students in the classes. Compute the multiple regression of rating on expected grade and number of stu- dents, and write a report on your findings.