Locate the Activity you would like to view the Ratings for (see find content in Find Learning or Content Manager if you're unsure how to do this) and go into its administration area.
Click on the Ratings tab on the left-hand side.
An average of the Ratings given will be displayed, as well as the individual Ratings and Comments that have been left by Users.
Tick the box next to one of the star Ratings to filter the results.