How are these numbers calculated?

Big Games

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

Week of 9/13100.0*Chance in playoffs100.0*Average seed
DC United 1 Miami 3 -21.9
-0.5
Revolution 3 Tampa Bay 0 -20.1
-0.8
Tampa Bay 2 New York 1 +18.7
+0.7
Miami 4 DC United 3 -9.0
-0.3
Dallas 1 Earthquakes 3 -0.1
New York 0 DC United 5 +0.1
Earthquakes 0 Galaxy 0 +0.0
Week of 9/20100.0*Chance in playoffs100.0*Average seed
Crew 3 Tampa Bay 4 +29.8
+1.8
Fire 3 Revolution 2 +3.5
+0.2
Galaxy 0 Earthquakes 1 -0.4
Revolution 0 New York 0 +0.1
Week of 9/27100.0*Chance in playoffs100.0*Average seed
Miami 1 Tampa Bay 3 In
+2.6
Earthquakes 2 Wizards 0 -0.3
Points
Chance Will Make Playoffs