How are these numbers calculated?

Big Games

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

Week of 4/13100.0*Chance wins title100.0*Average seed
Cheltenham Town 1 Gillingham 0 -1.3
Rochdale 2 Port Vale 2 +1.0
Week of 4/20100.0*Chance wins title100.0*Average seed
Gillingham 2 AFC Wimbledon 2 Yes
Port Vale 2 Northampton 2 Yes
Week of 4/27None
Chance Will Win Championship