Your default aggregation is natural. The "Weighted mean of grades" and "Sum of grades" grade book aggregation methods have been combined into a new dual-function method: "Natural" weighting. Natural is the sum of all grades scaled by weight, this allows each item to have a given point value with weights given to each category. The recommendation is to use the natural calculation method as it is the most flexible and can accomedate for extra credit.
Natural aggregation can function as a sum of grades when the weight boxes are left alone.
Natural aggregation can also function as a mean of grades, when the weight boxes are checked and then adjusted so that the weights are equal across a set of items in a category or a set of categories.
Items using the Natural calculation method can still be marked as "Extra credit" while using the weights to calculate a mean and contribute to the total for the category.
This documentation will show you how to verify and change the aggregation method by which your grade book will be calculated if needed.
First, locate the Administration block (typically in the left sidebar region of the course page). Under Course administration click on Gradebook setup. (OR once in the grades, click the Setup tab. )
Once in the Setup tab, click the Edit button the applies to the entire grade book (highlighted above).
Within the menu that pops up, click Edit settings. This will take you to the overall grade book settings for your course.
Under the Grade category section, you will see and drop down menu for Aggregation. Select you desired aggregation method from the drop down menu. NOTE: View descriptions of each aggregation method.
When you have made all your changes, remember to click Save changes.
Back on the Setup tab, you will see that the aggregation method you selected will be shown below Course total.
For more information, if you have questions, or otherwise need assistance, please contact your Instructional Technologist.