professor has found that the grades on a Statistics Exam are normally distributed with mean 72 and a standard deviation of 12. If only the best 15 % of the grades in the class will get an A, what grade must a student get in order to get an A?

Answer 1

Z = (score-mean)/SD

Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion/probability (.15) and its Z score. Insert Z value into above equation and solve for score.

Answer 2

answer:

x = 72 + (12*1.036) = 84.43