Turning a Positive Number Into a Positive for Probability

[Sabrosa]

Lets assume that team A and team B will play a match, and their powers are calculated like this:

A: 20
B: 10

From this; we conclude that A has a winning probability of 66.6%, and B has a winning probability of 33.3%.

Now let's assume that, using a model powers of team A and B are calculated like this:

A: 8.36
B: -7.15

How can the winning probabilities of team A and team B can be calculated ?
Please don't tell me to add +8 to both team's powers because it gives ridicilous probabilities. There should be a statistical way to find probability IMO. Does anyone know ?

Thanks in advance.

[RickySteve]

73.91%

[Sabrosa]

73.91%

Joke or real ?
If it's real, how ?

[bztips]

Hmmm, taking the square root of each number should do the trick... but that will require the use of imaginary numbers. Which should fit nicely with your use of imaginary handicapping.

[Peregrine Stoop]

maybe the differences between two rankings (assuming power is linear)

[Justin7]

We need a lot more info your power ranking system to offer any guidance.

[xbalto]

any system that calculates probabilities like in the first part cannot have negative numbers as scores. if the negative scores are real, something is fishy with the probability calculation.

[MonkeyF0cker]

73.91%

Hmm. I get 143.2%.