I am providing all my notes for training my faculty colleagues on the grade book because I think it baffles many when they first encounter it.
The answer to your specific question will be found at 5.a.vi.2.
5 Quick Steps to Setting up your Gradebook.
1. Make sure “advanced features” are visible
a. Click the button in “Set Preferences” tab
i. Currently, once this is clicked, you cannot subsequently hide these features. (This is a known bug, but not a really serious issue.)
2. Create Categories
a. Toward bottom of page
3. Associate activities with categories
a. If you wish to keep something out of Gradebook calculation temporarily, click the checkbox for extra credit
i. Click “Save Changes”
4. Set weightings
a. Uncategorized: Unless you actually use the “Uncategorized” category, set it to zero
b. Set weightings for each category as you desire.
i. Moodle will bark at you if it doesn’t add up to 100%
c. Drop Lowest X: You may drop 1 or more lowest scores in any category
i. Choosing this option requires that all items within the category be of the same point value.
d. Bonus Points: Add bonus points to compensate for lost points due to unfair questions, etc.
i. This is not extra credit; adding bonus points does not change the total point value for the category. It is also applied equally to all students.
e. Hidden: Clicking this means that that category will not used in grade calculations.
i. Note (from Help file): if this box is checked it will remove a category from display and also from grade calculation. This is an easy way to only add items to the gradebook after they have been graded. Since graded items that have not been categorized will automatically be assigned to "Uncategorized" you can set the "Uncategorized" category to hidden and then, as you grade items, move them to whichever category you like and students can then see their grades.
f. Click “Save Changes”
5. Set Preferences (Read the associated help file)
a. Recommended to keep as simple as possible so as not to confuse students
i. Use just one or two displays
ii. Choices are “No,” “To Teachers Only” and “Everyone”
1. Choosing “Everyone” does not allow students to see each other’s grades
iii. Weighted Grades: Determines whether the weighted percent will be displayed. You can also choose whether or not students see this.
iv. Display Points: Determines whether the points are displayed. Student settings can be adjusted separately from the instructor view.
v. Display Percent: Determines whether or not a percent is displayed. Student settings can be adjusted separately from instructor view.
vi. Display Letter Grade: Determines whether a letter grade is displayed for the course total.
1. Consider choosing to not show letter grades as these will normally be F at the beginning of the course and remain unsettlingly low until most of the course activities have been completed.
2. If you do wish to show letter grades that are accurate throughout the semester, you must remove uncompleted activities from the calculation by making them “extra credit” in the Set Categories tab, and clicking “Hidden” in Set Weights tab. You must then remember to un-do these settings as each activity is completed/graded.
vii. Letter Grade: Determines how the letter grade is calculated. Uses either a raw percent or weighted percent.
1. Recommend setting to “weighted” if you use weightings
viii. Reprint headers: Determines how often the column headings are reprinted.
ix. Show Hidden Items: Will show or hide grade items that are hidden. This applies to the instructor view only. Students will not see gradebook entries for items that are not visible to them. Student totals will include hidden items if this is set to "Yes"
1. Recommend setting to No.
Maintenance
1. Edit grades
a. Some modules such as the Lesson module may not permit editing.
i. If you find scores in such a module have been adversely affected by a “bad” question, you can compensate by using the “Bonus Points” box in the Set Weights tab.
2. The Grade Exceptions tab is used to remove from the grade calculation one or more assignments for individual students.
3. Manage Graded events is used to add new categories that have no corresponding activities in the course.
a. For example, if you assign students to see a play in the theater for extra credit, you can add that item here.
i. Note: Instead of doing this, however, you might as well create an “Assignment” activity in the course and then it will automatically be brought into the gradebook. Don’t forget to set it as extra credit in the Set Categories tab.
Miscellaneous Notes
1. If you have activities (or entire blocks) hidden in the course, then they will not show up in the gradebook.
2. You can see stats for individual gradebook items