Assume you have a class of approximately 800 students and following a set of assessments each student has a raw grade.
- How should these raw grades be converted into a final grade?
- Is it a good idea to scale the raw grades to a normal distribution?
Why should grades be normally distributed?
Sometimes they are but if the grades are not normally distributed then the bell curve grading system, where the middle say 70% get C's, is probably not a good one to base grades off of. Although that grading is pretty harsh, few instructors would actually do it.
Use distributions to describe the data, don't transform data to fit a particular distribution (although transformations can be helpful at times).
If you use the bell curve grading system and, extreme case, everyone aces the class. How do you decide grades?
Here is how I would decide final grades: