Choices in the Moodle gradebook may not function as you expect. Check the documentation and experiment with grades in an old course to be certain you get the results you want. We can provide access to test sites for your experiments.
The Moodle default is to have items that have not been graded not counted in the course grade. You can change this to have them calculated into the course total with a value of zero.
If you change the aggregation method between weighted mean of grades and mean of grades, calculations are different, and grades will almost certainly change.
By default, Moodle computes a final course grade based on the number of points earned divided by the number of points possible.
Note that these are points, not percentages. Grade items with fewer points give fewer grading options. For example, awarding two points to a four-point item is equivalent to a grade of 50%. To be able to grade an item on a 0-100 scale, you need to give it 100 points. (You can adjust the weight of grade items using categories.)
If you enter a grade in the Grader report that is higher than the maximum for an item, it will be rounded down to the maximum value you set for the item.
Grades can be displayed in the course as points, as percentages, as letter grades, or as any two of the three. This option is set in the Grade menu, under “Settings / Course”. Since the default letters in Moodle do not match the percentages used at Albright, displaying letter grades should be avoided.
Three common grading strategies.
I. Weighting by point value. (Simple weighted mean of grades)
final grade = Points earned / Points possible
Items are weighted based on their point value. If you have three quizzes worth 10 points each and a paper worth 30 points, the paper counts as much as the three quizzes together.
Grader report (editing on)
Student 1's grades are 8 + 8 + 8 + 24 for a total of 48 of 60 points. This is equivalent to a grade of 80%.
Student 2's grades are 9 + 9 + 9 + 21, also for a total of 48.
Student 3's grades are 5 + 7 + 0 + 24, for a total of 36 of 60 points, equivalent to 60%. If he earned 10 points for Quiz 3, his grade would increase to 76.66%.
II. Items given equal weight. (Mean of grades)
If the points given to an item are arbitrary and not intended to assign weight in computing the final grade, all items can have equal weight. The final course grade will be the average of all assignment grades.
Grader report (editing off, grades displayed as percentages)
final grade = Sum of grades (%) earned / Number of grades
Student Test 1's final grade is the average of 80% + 80% + 80% +80%, or 80%.
Student Test 2's final grade is the average of 90% + 90% + 90%, +70%, or 85%. Since all items are given equal weight, the result differs from the grades weighted by point value in I, above.
Student 3's final grade is 50%, but a grade of 100% on the quiz he missed would bring his final grade to 75%.
III. Weighting by category. (Weighted mean of grades)
This method is used if the instructor wishes to have different types of assignments have a fixed percentage or ratio in calculating the final grade. The weights of individual grade items can have an arbitrary total.
Categories and Items—Simple View
For example, the instructor can create a category for quizzes and one for papers. Each category is given a defined percentage or weight. Each assignment in the course is placed in its category. If the number of items in a category changes, the weight of the category will remain unchanged. Items not in a category should not affect the course grade—therefore every grade item should be in a category. An appropriate number is set as the course total.
Categories and items, Grader view
Additional information is available at the moodle.org site: