posted by Anonymous on .
The scores on an economics examination are normally distributed with a mean of 66 and a standard deviation of 14. If the instructor wishes to assign a grade of A to the top 10% of the class, what is the lowest score a student may have and still obtain an A?
Z = (score-mean)/SD
Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion (.10) related to a Z score. Then insert the values to solve for the score.