How are these numbers calculated?

Big Games

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

Week of 5/2100.0*Average seed
Bath 19 Northampton 19 +0.1
Week of 5/10100.0*Average seed
Leicester 31 Saracens 27 +0.2
Harlequins 19 Bath 16 +0.2
Northampton 74 London Wasps 13 -0.0
Games Above .500
Chance Will Make Playoffs