What is your strategy?

Discussion in 'Risk Management' started by kut2k2, Mar 28, 2014.

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  1. Visaria

    Visaria

    Give me a few mins, and I'll figure it out. Answer i gave yesterday was done in a min and late at night.
     
    #21     Mar 29, 2014
  2. Visaria

    Visaria

    Ok, i would bet:

    8% on R16,
    5% on R14
    24% on Red

    i.e those percentages of my bank each spin, (recalculating bank after each spin)
     
    #22     Mar 29, 2014
  3. Ok, thanks for the clarification. Here are my calculations.

    Optimal bet fraction = Kelly = p - (1- p) / b,
    where
    p = probability of winning
    b = odds on the bet

    Expectancy = p * b - (1 - p)
    My custom score = Expectancy * Kelly

    Then,
    Kelly(red) = 23/37 - (1 - 23/37) / 1 = 0.24 = 24%
    Kelly(black) = 13/37 - (1 - 13/37) / 1 = -0.29 = -29%
    Kelly(R14) = 3/37 - (1 - 3/37) / 35 = 0.05 = 5%
    Kelly(R16) = 4/37 - (1 - 4/37) / 35 = 0.08 = 8%

    Expectancy(red) = 23/37 * 1 - (1 - 23/37) = 0.24
    Expectancy(black) = 13/37 * 1 - (1 - 13/37) = -0.29
    Expectancy(R14) = 3/37 * 35 - (1 - 3/37) = 1.92
    Expectancy(R16) = 4/37 * 35 - (1 - 4/37) = 2.89

    Score(red) = 0.24 * 0.24 = 0.058
    Score(black) = no need to calculate, negative expectancy and negative Kelly
    Score(R14) = 0.05 * 1.92 = 0.096
    Score(R16) = 0.08 * 2.89 = 0.231


    So, if only a single bet is allowed, the best strategy would be to bet 8% of the bankroll on R16, on every bet. Some sort of combination bet (such as R14 and R16) would probably be even better, but I have not calculated it yet.
     
    #23     Mar 29, 2014
  4. Visaria

    Visaria

    The problem is the overlap between r14,r16 and red...i think i would need to bet less than what i just said for RED, maybe only 20% on RED?
     
    #24     Mar 29, 2014
  5. kut2k2

    kut2k2

    Excellent analysis.

    I agree, the best bet is almost certainly going to be some combination bet, possibly of all three +ev singles.

    I love the challenge. :)
     
    #25     Mar 29, 2014
  6. Yes, your original proposal (a combo bet of 8% on R16, 5% on R14, 24% on Red) is almost certainly an overbet. I am not sure if it's possible to solve for the optimal combination bet analytically, but it can certainly be done numerically using a simulation.
     
    #26     Mar 29, 2014
  7. dom993

    dom993

    I am most certain Kelly fraction & such doesn't apply because of the 10-spin limit

    Betting 1 on red every spin, the average ending P&L on 10 spins is +2.43 with a stdev of ~3.05
    Betting 1 on red-16 at every spin, the average ending P&L on 10 spins is +28.92 with a stdev of ~35.4

    (stdev from MC-sim on 100,000 runs in both cases, unlikely to be the "exact" value)

    The information-ratio (avg/stdev) is 0.797 for red-single, and 0.817 for red-16

    I would say the difference between the 2 is marginal at best, IMO those 2 plays are equivalent.

    This "opportunity" still present the risk of ending with a negative P&L about 20% of the time, regardless of play red or red-16.

    The optimal bet is the one that guarantees the ending P&L will stay within the player desired boundaries after the 10-spins.
     
    #27     Mar 29, 2014
  8. kut2k2

    kut2k2

    Best combo so far:

    Bet 9% of bankroll on Red plus 9% of bankroll on R-16.

    Kelly == 0.179 ,
    Expectation == 58/37 == 1.568 ,
    k*E == 0.2806
     
    #28     Mar 29, 2014
  9. Visaria

    Visaria

    I was a bit confused about whether you can bet on both R14 AND R16, the opening post says :

    - You are only allowed to place one of these types of bets:
    -- Any single number (including R-16, R-14, G-0), which pays off at 35-1 ,
    -- Red or Black, which pays off at 1-1.

    But then says:

    - You are allowed to place multiple bets on the same spin.
     
    #29     Mar 29, 2014
  10. kut2k2

    kut2k2

    Kelly is the way to bet even if there's a one-spin limit. Your analysis is wrong.
     
    #30     Mar 29, 2014
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