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Maths 101 - For all US Sportsbettors

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  • Maths 101 - For all US Sportsbettors

    OK Fellas, i've been reading this forum for a while now and can't help being frustrated when reading posts such as "who pays the vig" or "the 10c - 20c debate". Basically, because you yanks are so worried about how many cents are in the line, you forget about the probability that these lines represent. This is why the US format is a BAD system. I have come to educate you.

    Every single price is just a probability, with juice added. A 50-50 game, at true odds, is +100,+100, or 2.00, 2.00. (to convert a US price to a REAL price, if it is a +, put a decimal after the first digit and add 1 eg. +235 = 3.35. If it is -, put in your decimal point, add one, then divide by the original number eg. -135 = 2.35/1.35 = 1.74).

    Now, if a BM wants to charge, say 2% on this 50-50 game because it is baseball, it is just a matter of adding to the %. He will add his % up to 102.12 to get a THEORETICAL HOLD of 2%. ie. ((102.12-100)/102.12)*100=2. The 2% is the actual winnings provided there is equal action and no line movement (appropriately called theoretical because this NEVER, EVER happens). Now, if we go 102.12*.05 = 51.06 therefore, for a 50% chance, you must pay 51.06. To convert this to a price, 100/51.06 = 1.96 (-104). So that's who pays the juice, EVERYONE who bets without an edge, because EVERYONE has to pay for a higher % than what is actually true. How you can come up with no juice on dogs in baseball, or only winners, or only losers paying vig on pointspreads is beyond me. Every time you bet against a house edge, you pay juice. A baseball game at a true 2% hold is -104 pk, however, the BM's figured that 10c was close enough.

    Now, -110 (1.91) goes like this:
    (100/1.91)*2 = 104.71. ((104.71-100)/104.71)*100 = 4.5% Therefore, betting pointspreads in the long term, you will lose 4.5% of what you bet playing without an edge. I've seen things such as "10% juice on winning bets" when it should should read "4.5% juice on all bets".

    Now, here's the scary thing. Many posters here claim a true 10c line should go to -200. OK, -200 = 1.5, +190 = 2.9.
    (100/1.5)+(100/2.9)=101.14!!!. ((101.14-100)/101.14)*100= 1.13% that the BM will win. You gotta wonder about a BM who will let his line go this fine just so it reads a nice, simple 10c!, and who will move his line from -200 to -205 the same as he would -105 to -110 just because his standard move is 5c! Bettors, if you find these books, only play into lines -180 to -200 and you only have to beat just over 1%. Shop your numbers and there it is. Juice free betting!
    Why do you think Lennox Lewis doesn't go from -1600 to -1610!. Because you are moving %'s, not cents! That's why!

    IMHO, a line should be kept at a constant hold %, so baseball should be -104pk, -130 +110, -150 +138, -200 +183.

    I have done this for my mathematically challenged friends there in the USofA for your benifit, after all, you did save our arses in WWII . Just please do one thing for me......get the @$!*ing metric system!

  • #2
    -110 isn't 1.91 though...

    not just percentages

    tax impacts as well

    Comment


    • #3
      AV2,

      -110 is 1.9090909. Close enough huh?

      And tax is still juice, and tax only impacts if you bet into those small euro joints, and is incorporated into the %. Trust me, I know.

      c'mon mate, don't throw a spanner in the works

      Comment


      • #4
        Thanks mug - easily understandable analysis.

        Comment


        • #5
          Absolutely right on the money, mugmoney. (even if it was explained a little condescendingly! )

          Hope you don't mind if I simplify the math. If x and y are the "European odds", then the %age hold is:

          (1/x+1/y)-1

          The cool thing about this is is doesn't matter how many bet offers are available (like in soccer when a tie option is available), all you have to do is add another 1/x term and the formula holds:

          e.g. Arsenal-Manchester United 2.4-2.9-2.9

          %age hold= 1/2.4+1/2.4+1/2.9-1 = 10.6%

          This is especially useful when you have something like a future book for a championship and 20 or 30 teams to choose from.

          I hope JR is reading this!

          [This message has been edited by PerpetualCzech (edited 07-25-2000).]

          Comment


          • #6
            Originally posted by mugmoney:
            AV2,

            -110 is 1.9090909. Close enough huh?

            And tax is still juice, and tax only impacts if you bet into those small euro joints, and is incorporated into the %. Trust me, I know.

            c'mon mate, don't throw a spanner in the works

            Not if you are going to indulge in 2 decimal place calculations it isn't - tax also as in tax on turnover, etc., another reason why odds will be split how they are, as explained previously by a bookie.

            Comment


            • #7
              I think the American bookmakers would like to keep their line format when I keep seeing questions like

              'how do you calculate the return on a baseball parlay'

              can't be bad for them.

              Comment


              • #8
                The good point here being though all 'cents' are not created equal, so a '30 cent' edge at -170 is not the same as a '30 cent' edge at +100 - something that is obvious to the non mathematically challenged (but not to a lot of punters, I guess)

                Comment


                • #9
                  -- let's see how this turns out from the betting ring, as an example of some approximations

                  ODDS PAYS % ODDS PAYS % ODDS PAYS %
                  1/100 -10000 1.01 99.0 1/50 -5000 1.02 98.0 1/33 -3330 1.03 97.1
                  1/25 -2500 1.04 96.1 1/20 -2000 1.05 95.2 1/16 -1600 1.06 94.1
                  1/14 -1400 1.07 93.3 1/12 -1200 1.08 92.3 1/11 -1100 1.09 91.7
                  1/10 -1000 1.10 90.9 1/9 -900 1.11 90.0 1/8 -800 1.13 88.9
                  1/7 -700 1.14 87.5 10/65 2/13 -650 1.15 86.7 1/6 -600 1.17 85.7
                  10/55 2/11 -550 1.18 84.6 1/5 -500 1.20 83.3 10/45 2/9 -450 1.22 81.8
                  1/4 -400 1.25 80.0 10/38 -380 1.26 79.2 4/15 -375 1.27 78.9
                  10/35 2/7 -350 1.29 77.8 3/10 -333 1.30 76.9 10/32 4/13 -325 1.31 76.4
                  10/30 1/3 -300 1.33 75.0 10/28 -280 1.35 73.7 4/11 -275 1.36 73.3
                  10/27 -270 1.37 73.0 10/26 -260 1.38 72.2 10/25 4/10 -250 1.40 71.4
                  10/24 -240 1.42 70.6 10/23 -230 1.43 69.7 4/9 -225 1.45 69.2
                  10/22 -220 1.46 68.8 10/21 -210 1.48 67.7 10/20 1/2 -200 1.50 66.7
                  10/19 -190 1.53 65.4 8/15 -185 1.54 65.0 10/18 -180 1.55 64.3
                  4/7 -175 1.57 63.7 10/17 -170 1.59 63.0 6/10 3/5 1.60 62.5
                  8/13 -165 1.62 62.1 10/16 -160 1.63 61.5 -155 1.65 60.8
                  10/15 4/6 -150 1.67 60.0 7/10 -145 1.70 59.0 10/14 -140 1.72 58.3
                  8/11 -135 1.75 57.4 10/13 -130 1.77 56.5 8/10 4/5 -125 1.80 55.6
                  10/12 -120 1.83 54.5 85/100 1.85 54.0 -115 1.87 53.5
                  9/10 -111 1.90 52.6 10/11 -110 1.91 52.4 -105 1.95 51.2
                  EVENS 1/1 -100 2.00 50.0 +105 2.05 48.8 11/10 +110 2.10 47.6
                  10/9 +111 2.11 47.4 +115 2.15 46.5 12/10 6/5 +120 2.20 45.5
                  5/4 +125 2.25 44.4 13/10 +130 2.30 43.5 +135 2.35 42.6
                  11/8 2.38 42.1 14/10 7/5 +140 2.40 41.7 +145 2.45 40.8
                  15/10 6/4 +150 2.50 40.0 +155 2.55 39.2 16/10 8/5 +160 2.60 38.5
                  13/8 2.62 38.1 +165 2.65 37.7 17/10 +170 2.70 37.0
                  7/4 +175 2.75 36.4 18/10 9/5 +180 2.80 35.7 +185 2.85 35.1
                  15/8 2.88 34.8 19/10 +190 2.90 34.5 +195 2.95 33.9
                  2/1 +200 3.00 33.3 21/10 +210 3.10 32.3 22/10 11/5 +220 3.20 31.3
                  9/4 +225 3.25 30.8 23/10 +230 3.30 30.3 24/10 12/5 +240 3.40 29.4
                  25/10 5/2 +250 3.50 28.6 26/10 13/5 +260 3.60 27.8 27/10 +270 3.70 27.0
                  11/4 +275 3.75 26.7 28/10 14/5 +280 3.80 26.3 29/10 +290 3.90 25.6
                  3/1 +300 4.00 25.0 32/10 16/5 +320 4.20 23.8 13/4 +325 4.25 23.5
                  100/30 4.33 23.1 35/10 7/2 +350 4.50 22.2 15/4 +375 4.75 21.1
                  38/10 +380 4.80 20.8 4/1 +400 5.00 20.0 42/10 17/4 +425 5.25 19.1
                  45/10 9/2 +450 5.50 18.2 5/1 +500 6.00 16.7 55/10 11/2 +550 6.50 15.4
                  6/1 +600 7.00 14.3 65/10 13/2 +650 7.50 13.3 7/1 +700 8.00 12.5
                  75/10 15/2 +750 8.50 11.8 8/1 +800 9.00 11.1 9/1 +900 10.00 10.0
                  10/1 +1000 11.00 9.1 11/1 +1100 12.00 8.3 12/1 +1200 13.00 7.7
                  13/1 +1300 14.00 7.1 14/1 +1400 15.00 6.7 15/1 +1500 16.00 6.3
                  16/1 +1600 17.00 5.9 18/1 +1800 19.00 5.3 20/1 +2000 21.00 4.8
                  22/1 23.00 4.4 25/1 26.00 3.9 28/1 29.00 3.5
                  30/1 31.00 3.2 33/1 34.00 2.9 35/1 36.00 2.8
                  40/1 41.00 2.4 45/1 46.00 2.2 50/1 51.00 2.0
                  55/1 56.00 1.8 60/1 61.00 1.6 66/1 67.00 1.5
                  70/1 71.00 1.4 75/1 76.00 1.3 80/1 81.00 1.2
                  90/1 91.00 1.1 100/1 101.00 1.0 125/1 126.00 0.8
                  140/1 141.00 0.7 150/1 151.00 0.7 160/1 161.00 0.6
                  200/1 201.00 0.5 250/1 251.00 0.4 330/1 331.00 0.3
                  400/1 401.00 0.2 500/1 501.00 0.2 1000/1 1001.00

                  Comment


                  • #10
                    ok, it doesn't paste great, but can be copied and pasted, or found here :-
                    http://www.betting-ring.com/per.html

                    Comment


                    • #11
                      A major problem with american odds for me has been dealing with them in spreadsheets.

                      I've tried to convert american odds to european in some of my databases but can't.

                      Anyone know of a formula to do this on a spreadsheet? How do others deal with this problem?

                      Comment


                      • #12
                        Alex:

                        Formula when x is negative is

                        -100
                        y = ------- + 1.0
                        x

                        eg..
                        x = -125 which is 4/5on from OZVamp and OZ bookies table

                        -100
                        y = ------- + 1.0
                        -125


                        y = 0.8 + 1.0


                        y = 1.8 (european coefficients)

                        When x is positive
                        x
                        y = --- + 1.0
                        100



                        I like OZVamp grew up with Australian bookmaker odds & in particular South Australian which are different from Victorian and New South Wales and even Englysh!!!

                        I see that Victorian Bookies are being converted to decimal!!!! XA XA XA!

                        FF


                        [This message has been edited by Fedya Fussball (edited 07-25-2000).]

                        Comment


                        • #13
                          Money great post!!! Bear with me.

                          Example: Mariners -130 at one joint Mariners -140 at another joint using a 10 cent line. Is there an edge there and how do you figure how much of an edge if there is one there?

                          BTW, I think there is one there but as you said I'm mathematically challenged and would like to find out how to figure this. Thanks!

                          Comment


                          • #14
                            Mugmoney,

                            Willing to make a few concessions:
                            Maybe the metric system is better.
                            Maybe the decimal system is also superior, definately helps when one has to play trebles.

                            Request in return:
                            1) Euro Bookmakers drop the tie's lose crap on golf and boxing.
                            2) Euro Bookmakers adopt a -.5/+.5 line on events where the tie is a legitimate outcome.
                            3) Euro Bookmakers, when faced with a winning player, do not limit that player to ridiculously low wager levels.
                            4) Euro Bookmakers lower their hold in general to the 3-5% range.

                            If you can get any 2 of those 4 accomplished, I am pretty sure we can get that metric system in place and maybe even decimal odds.

                            Comment


                            • #15
                              Mugmoney wants to see the decimal because he's a wanna be Aussie. Right Mug. Your still trying to fit in over there. How bout it mate. E-mail me, would like to say howdy.

                              scottoscar@hotmail.com

                              Don't bother emailing if your first name doesn't start with a M. But I'll bet you a kangaroo steak I'm right.

                              Comment

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