How are these numbers calculated?

Big Games

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

Week of 4/15100.0*Chance in playoffs100.0*Average seed
Duluth High Sch 2 Meadowcreek Hig 0 +27.2
+1.2
Mill Creek High 2 Peachtree Ridge 0 +3.6
+0.1
Mountain View H 0 Habersham Centr 4 -3.6
-0.1
North Gwinnett 0 Mill Creek High 1 -0.2
Week of 4/18100.0*Chance in playoffs100.0*Average seed
Habersham Centr 1 Duluth High Sch 2 In
+1.0
Norcross High S 2 Duluth High Sch 5 +0.8
Collins Hill Hi 0 Peachtree Ridge 3 -0.1
Peachtree Ridge 2 Norcross High S 1 +0.0
Points
Chance Will Make Playoffs