If you developed your own component or module that does not perform any DB access (no specific table) then you can just defined the extension.
Concerning the google analytics, I suppose you make reference to our free multisites google analytics module.
As the parameters are saved in the module they are specific for each website.
So just add the module in a specific position (ie. footer or main menu, ..) and setup the google code.
See the multisites google analytics description that will guide on you the different setting
www.jms2win.com/en/free-download/doc_det...tes-google-analytics