How are these numbers calculated?

Big Games

How we did last week and who we should root for this week.   Explain

Week of 6/8100.0*Chance wins title100.0*Average seed
Canada 36 Tonga 27 -0.6
+0.0
USA 9 Tonga 18 No
-0.3
Week of 6/19100.0*Chance wins title100.0*Average seed
Japan 16 Canada 13 -0.2
Fiji 35 USA 10 -0.1
Week of 6/23100.0*Chance wins title100.0*Average seed
Japan 38 USA 20 -0.1
Games Above .500
Chance Will Win Championship