The aggregate type defines how ratings are combined to form the final grade in the gradebook.

* Average of ratings - The mean of all ratings
* Count of ratings - The number of rated items becomes the final grade. Note that the total cannot exceed the maximum grade for the activity.
* Maximum - The highest rating becomes the final grade
* Minimum - The smallest rating becomes the final grade
* Sum - All ratings are added together. Note that the total cannot exceed the maximum grade for the activity.

If "No ratings" is selected, then the activity will not appear in the gradebook.