Id like to know about the sond rating system

will it make a high rated song to play more often when playing randomly?

No, but if you use Rhapsody, the rating syncs back to your Library when you connect, and then you can create a “Dynamic Playlist” with criteria based on the rating.

For example, I have a “Highly Rated” playlist that chooses fifty songs with a rating of 4 or 5 from my Library and then moves them to my Fuze on sync.