How are these numbers calculated?

Big Games

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

Week of 1/5100.0*Chance in playoffs100.0*Average seed
Newcastle 1 Central Coast 0 -28.6
-0.8
Central Coast 0 New Zealand 0 -6.2
-0.2
Week of 1/12100.0*Chance in playoffs100.0*Average seed
Melbourne 1 Brisbane 2 -6.0
-0.2
Adelaide 1 Sydney 0 Out
-0.1
Perth 3 Newcastle 3 Out
Week of 1/19None
Points
Chance Will Make Playoffs