A teacher informs his macro economics class (of 500 students) that a test was very difficult, but the grades would be curved. Scores on the test were normally distributed with a mean of 29 and a standard deviation of 9.5. The maximum possible score on the test was 100 points. Because of partial credit, scores were recorded with 1 decimal point accuracy. (Thus, a student could earn a 29.1, but not a 28.02.)
The grades are curved according to the following scheme. Find the numerical limits for each letter grade.
Letter Scheme Interval
A Top 8%
B Scores above the bottom 70%
and below the top 8%
C Scores above the bottom 30%
and below the top 30%
D Scores above the bottom 8%
and below the top 70%
F Bottom 8%