1. #1
    Stocks
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    Question about Kelly and calculating your edge

    If someone has a 55% winning percentage at average odds of -107 and they want to bet Atlanta Braves +150.

    What is your overall edge?

    How do you find your win probability for that game?

    Is your overall edge 3.3% and if so would your win probability for a +150 game be 43.3%

    or

    Is your overall edge is 3.3% and your win probability for a +150 game would be 41.32%

    Thanks
    Last edited by Stocks; 02-17-12 at 03:40 PM.

  2. #2
    Romanov
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    Past winning percentage has nothing to do with edge. If the individual game has a 55% probability to go one way and you can get it at -107:

    .55/(107/207) - 1 = edge = 6.4%

    Or if you somehow had a game with 55% prob and odds of +150:

    .55/(100/250) - 1 = edge = 37.5%

  3. #3
    Stocks
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    Are you sure past performance has nothing to do with edge? If you bet 5000 baseball games and hit 55% at -107 wouldn't it be safe to say you have a 3.3% edge in baseball?

    55% at -107 odds = 3.3% edge (overall edge)

    Atlanta +150 = 40% (breakeven point)

    40% x 3.3% = 41.32% (win probabilty)

    1.50 x 41.32% = 0.6198 (betting odds x win probabilty)

    1 - .4132 = 58.68% (losing probabilty)

    0.6198 - .05868 = 0.033 (betting odds x win prob - lose prob)

    0.033 / 1.50 = 0.022 (number above / betting odds)

    Answer 2.2%

    That was the same answer I got on the kelly calc

  4. #4
    Stocks
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    Ok I see how you got the 6.4% but couldn't we still say we would have an average 6.4% edge in each game?

  5. #5
    Romanov
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    Quote Originally Posted by Stocks View Post
    Ok I see how you got the 6.4% but couldn't we still say we would have an average 6.4% edge in each game?
    each game is an independent event (kinda) so no.

  6. #6
    FourLengthsClear
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    Using a historical record as a basis for establishing an edge for future matches is not recommended.

    You can say that your edge to date has been 6.4% (+/- the effects of variance).

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