Subdomain tracking – how to

I have two subdomains:

http://www.site.com
blog.site.com

Blog runs WordPress and I setup analytics for subdomains. I just need to setup the “Subdomain Tracking:” in plugin settings.

Now I’m not completely sure because it’s nowhere stated exactly – but should I put “blog.site.com” in this setting or something else?

thanks

http://ww.wp.xz.cn/extend/plugins/google-analytics-for-wordpress/