You can delete individual responses if needed. Note that after deleting any data it cannot be retrieved. Check the instructions below.
Go to Analytics
Choose the Response List view from the upper right corner of the page
Set the filters based on which survey responses you are looking to delete
After the Dashboard has loaded the responses, scroll the page to the right until you see the trashcan icon after each response. Click on the icon and confirm the deleting of the response.
Note that a delete can't be undone, so make sure you are deleting only responses that you are certain that you won't need anymore
All deleted responses will also be removed from the overall scores on the Summary and Analytics page.
Note that you can't remove responses if your role is a "Viewer". Only "Editor" or "Admin" accounts can remove responses.