Math question re: finding percentage of winning

[King Kyle]

Hey guys,

Been following in the shadows for quite some time now. Figure its bout time I ask questions and start to learn from the best.

First questions I have both relate to winning percentages and how to find them.

Theoretically it is 100 ÷ x = teams winning percentage, with x being the decimal odds. So if it is paying 3.00 their winning percentage is 33.333... My question for this is how do you determine the true percentage including vig? No book offers 2.0 each way (which would be a true 50% if following the equation mentioned earlier). Or am I over thinking it and just don't the way I have been?

My other question is about ties, not for soccer as a soccer tie has a listed line already.

But for college basketball/football. Where do you look or how do you find the odds needed? My thoughts for college basketball is that you need find what is each teams winning chances are to win by 6 are, add them together and subtract from 100 and that number is the chance of tie? If that's true, do you determine what the odds should be by doing 100 ÷ % = decimal odds for tie?

If the line is set at -3.5, how are you able to determine what the percentages/odds should be for a tie when it is 5.5 each way?

I hope these questions are clear enough, and I hope neither have been discussed before as I wasn't able to find either.

I appreciate anyone who takes the time to try and help me out.

[richhhh]

Formula for removing the vig and calculating a winning percentage from a money line.

1.775 vs 2.17

(1/1.775)/ ((1/1.775)+(1/2.17))
(.5633)/((.5633)+(.4608))
(.5633)/(1.0241)
= .55


Same idea with the 2.17

1.775 vs 2.17

(1/2.17)/((1/2.17)+(1/1.775))

[bangminton]

Kyle, for your second question, I believe PLP has an extensive database of College Ball games that he uses for CBB calculations. 30% seems to be the number for ties. There are a number of factors at play when calculating ties, including spreads and totals.

http://www.prolineplayer.com/Reports/ExpectCbb.php

[King Kyle]

Thank you both...

Richhhh - I have added this to my excel files for future reference.

Bangminton - I was racking my brain trying to figure it out and I was coming up empty every time. The historical data/spreads/totals makes sense.

Payday is coming soon, and so will my subscription to the site.

[richhhh]

I just assumed the cbb tie lines would be calculated the same way .Teams A's winning probability by -5.5 + Team B's probability of winning by -5.5 and the tie probability would be found by subtracted those two probability's by 100. I am guessing maybe those lines are not widely available and this is why a point based model is used from the money line and total?

[bangminton]

Rich, if you do a search for college basketball tie, you will find a post from PLP around May 2013 explaining his method. I'm using my phone so can't copy and paste link easily.