The principle of curving grades is that the performance of members of a class is evaluated on the basis of the highest-performing individual in the group. This means that the difficulty of a test is adjusted to the ability level of the class.
The calculation is a simple percentage, that sets the highest value at 100%.
Example:
| The best grade on a test is 87. You made 75. |
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Calculate: (Your grade / Highest Grade) X 100 = Curved Grade
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75 / 87 X 100 = 86.2% (Notice that the star student’s grade is 87/87 = 100%)
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WebCT will keep track of all work you submit in a spreadsheet that I can access. I download this data to an Excel spreadsheet, which is my official grade book. I add the results of hand-graded assignments to this page. I enter formulas into the spreadsheet that will "do the math" to calculate your course points. This is NOT the "My Grades" feature in WebCT Vista.
Assignments and tests usually are graded on a 10-point basis: 100 points is a perfect score; 90-100 = A, 80-89 = B, etc.
Various assignments have different weights, expressed as percentage values. The percentage point value of each course requirement is listed in your syllabus. Therefore, a grade of 90 on an assignment that represents 40% of your course points is worth more to you than a grade of 90 on an assignment that represents 10% of your course points. (Think about the difference between an ounce of celery and an ounce of chocolate candy.)
Mathematically, it works this way: If you earn a grade of 100 on an assignment that is worth 2% of your course grade, this will add 2 points to the total course points. If you earn a grade of 100 on an assignment that is worth 15% of your course grade, the total will increase by 15 points. A passing grade is 60 points; 100 is the maximum possible.
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To calculate the course points earned
by an assignment, multiply the grade by the decimal form of the percentage
value of the assignment. Example: You earn a grade of 84 on an
assignment that is worth 15% of your final grade. So, |
Course point calculation gets pretty interesting in the Excel spreadsheet, where subtotals and dropped grades must be figured into the calculation. It usually involves a formula that gets information from other formulas. If you want to see how your particular class formula works, come in during office hours and I will be glad to show you. Later in a semester, if there is time, I will go over this in class.
| What do I need on
the final to get a certain grade for
the course? If you have grades posted for everything else, then the maximum number of points that the final exam can add is the same as its percentage value. For example, you earn 15 points if the final is 15% of your course grade and you make a perfect score. |
| Demonstration: Test grade you need = Course points you want to add ÷ percentage value (as a decimal) of the test The final is worth 15%. You have 57 course points. You want to make a C. Therefore you need 13 more points to total 70 course points, which is the lowest C. Needed Test Grade = 13 / 0.15 = 86.67 You need to make a solid B on your final to score a C for the course. |
About decimals--if you try to duplicate any grading computation on a handheld calculator, there may be a slight difference in the outcome as compared to WebCT when there are fractional points involved. This is because WebCT does its math in a mainframe computer that solves to more decimal values than a handheld can manage. The difference is not significant, but it may occasionally appear.
If all of this is more information than you really wanted to have, just remember that the total number of course points increases throughout the semester. You need 60 points for a D.