6. [11 marks] Suppose we are provided with a DataFrame grades that contains students' grade information. Here are the first four rows of grades. SID midterm final score_UG score_GR type 0 552 69 93 1 129 86 96 2 412 91 63 888 95 94 undergrad 93 98 grad 87 82 undergrad 3 623 95 93 92 92 94 undergrad The meaning of variables is listed below, SID is a student's ID number. midterm and final contain a student's midterm and final exam score, as a percentage. score_UG contains a student's final grade in the class according to the undergraduate grading scheme. score GR contains their final grade according to the grade grading scheme. type tells us if a student is an undergraduate or graduate student. (a). (1 mark) What type of variable is SID? 3-(final exam score)+(midterm exam score) (b). (2 marks) We define a student's "weighted exam score" as Write a line of Pandas code that determines the average weighted exam score for all students in the class. Feel free to use numpy methods. Lenovo Vantage