The next two questions (36 and 37) refer to the following: Percentage grades in a large geography class follow a normal distribution with mean 67.5 and standard deviation 12.5. 36. What proportion of students in the class receive percentage grades between 60 and 70? (A) 0.2650 (B) 0.2750 (C) 0.2850 (D) 0.2950 (E) 0.3050 37. The professor decides to assign a grade of A+ to the students with the top 8% of the grades, and a grade of A to the next best 12%. What is the minimum percentage a student needs to earn a grade of A? (A) 77 (B) 78 (C) 79 (D) 80 (E) 81(E) 12C 35. What is the value z such that P(-z