The marks for a first year Biology course at Delta University are normally distributed. The professors decide to award final grades using the following system:
• the top 5% of studens will receive an A.
• the next 15% of students will receive a B.
• 60% of the students will receive a C.
• 15% of the students will recieve a D.
• 5% of the students will receive an F.
Jason has a final grade of 77% in the course. The mean is 64% and the standard deviation is 7%.
(a) What is Jason's z-score?
(b) Find the letter grade that Jason will get in the course.
(c) With a minimum of a B letter grade, Stephanie will maintain her basketball scholarship. What is the minimum grade, as a percent, that Stephanie must obtain in the biology course to earn a B?
Solution