If you want to exclude a specific grade of an activity for a specific student, follow the steps below:
Step 1: Locate the Administration block, then expand Course administration and click Gradebook setup.
Step 2: From the Grade administration menu (that appears within the gradebook context), click Grader report. Alternatively, from the gradebook setup page, you can access the grader report by clicking the View tab.
Step 3: When displaying the grader report, click Turn editing on. (Located in its usual top-right location)
Step 4: Click the gear icon (edit button) in the cell corresponding to the grade you want excluded from calculation. This will open the Edit grade page.
Step 5: To exclude the grade, make sure Excluded is checked. Then click Save changes. This will cause your gradebook to be recalculated, this is expected.
Step 6: Click Continue.
You can verify, by viewing the grader report, that the grade has been excluded by observing the red Excluded label that now shows in the grade cell.
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