A teacher informs her computational physics 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 32 and a standard deviation of 7.8.
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 32.4, but not a 31.67.)
The grades are curved according to the following scheme. Find the numerical limits for each letter grade.
The grades are curved according to the following scheme. Find the numerical limits for each letter grade.
| Letter | Scheme | Interval |
|---|---|---|
| A | Top 15% | |
| B | Scores above the bottom 72% and below the top 15% | |
| C | Scores above the bottom 28% and below the top 28% | |
| D | Scores above the bottom 15% and below the top 72% | |
| F | Bottom 15% |