bigpete88
bigpete88
Joined: Mar 8, 2011
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September 16th, 2012 at 3:06:24 PM permalink
Thanks MangoJ for correcting me in the first place that more bets at +EV is better.

I am not asking about variance of bet size if that was your question. I am guessing that the standard deviation will be less at 9% ROI than 3% as 7Craps had spelled out.

Odds at -110 to win 100 just for this example.
7craps
7craps
Joined: Jan 23, 2010
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September 17th, 2012 at 7:51:49 AM permalink
Quote: bigpete88

I am guessing that the standard deviation will be less at 9% ROI than 3% as 7Craps had spelled out.

Odds at -110 to win 100 just for this example.

For 54% win rate one can have a 3.09% ROI
for 1 trial and $1 bet
ev: 0.0309
sd: 0.9515
for 400 trials and $110 bets
ev: 1,360.0000
sd: 2,093.2692
ROI% SD: 4.75743% (SD / handle)
Probability of being in the hole after 400 wagers: 25.794255% (about 1 in 4)

For 57% win rate one can have a 8.82% ROI
for 1 trial and $1 bet
ev: 0.0882
sd: 0.9451
for 400 trials and $110 bets
ev: 3,880.0000
sd: 2,079.3182
ROI% SD: 4.7257231% (SD / handle)
Probability of being in the hole after 400 wagers: 3.1020941% (about 1 in 32)

I would be more concerned that my 2% bet size is not over-betting my advantage since the win rate in sports betting is a variable.
This has been already talked to death by many experts.
Edward Thorp comes to mind in his "The Kelly Criterion in Blackjack, Sports Betting and the Stock Market" paper

ROI is still a very weak number to rely on. Variance works on that also for small number of trials.

reminds me of
Just like the cry-baby "tax the rich even MORE" goofballs with the billionaire pays less tax rate than the secretary bulls**t.

Let us see,
12% of $28,000,000 = $3,360,000 in taxes paid

The secretary pays a whopping 17% (41.7% MORE than the rich guy - this IS a fuc*ing crime!),
and the cry-babies- are still crying about that one...
17% of $60,000 = $10,200 in taxes paid

Now, Who over-payed, in actual $$$s, for the same government services???

The rich guy paying the f***ing low tax rate??
The cry-babies say so.
A**holes, all of them
winsome johnny (not Win some johnny)
BettingNation
BettingNation
Joined: Mar 15, 2017
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March 15th, 2017 at 6:01:08 AM permalink
I can't figure another way to lower the variance but I'm sure you will find something in (link removed by mod) you want you can check it out. It worked fine for me.

(Mod comment: pretty sure this was spam but could have been an offer to help. So stopping with a warning to BettingNation for now.)
Last edited by: unnamed administrator on Mar 15, 2017
bazooooka
bazooooka
Joined: Nov 21, 2016
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April 12th, 2017 at 11:59:21 PM permalink
For those who are good at betting math? What's the odds that someone who is a $500 sports bettor (-110) is up $5000 after only 150 bets places?

What's the odds this is chance (assume 50/50 odds for each bet) vs skill (bettor has an edge somehow)?

Thank you
beachbumbabs
Administrator
beachbumbabs
Joined: May 21, 2013
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April 13th, 2017 at 12:15:37 AM permalink
You're talking a record of 86-64 or so, with the vig making it not come out quite right. So a 57.33% win rate. That doesn't seem extraordinary to me, as we have an NFL contest each year here, and out of 20 or 30 playing each year, 6 or more will be above that rate at 150 games (see the various NFL picks threads here).

I could be wrong. Certainly with the bets so large, it's a nice chunk of change, but I would think it's run good rather than great picking.
"If the house lost every hand, they wouldn't deal the game."
bazooooka
bazooooka
Joined: Nov 21, 2016
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April 13th, 2017 at 12:44:18 AM permalink
What if it took 1500 bets instead of the 150 would that imply skill (albeit very slight) since one is only getting 10 units of profit after 1500 bets? Or would a good run last this long?

At some point things head to 50/50 and the vig crushes you but when can we see if it's skill vs luck.
bazooooka
bazooooka
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April 14th, 2017 at 3:07:31 PM permalink
Near 60% win rates do quite well in the NFL Super Contest. You'd place and make 25K or more just by making the top 25. I suspect that having many 57% winners in the picks contest here has something to do with stale lines and sharp players.

I would like someone mathematical inclined to show how may picks that'd require before concluding 57% is skill vs luck; would 300 picks suffice? 1000?
RS
RS
Joined: Feb 11, 2014
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April 14th, 2017 at 6:48:05 PM permalink
Quote: bazooooka

For those who are good at betting math? What's the odds that someone who is a $500 sports bettor (-110) is up $5000 after only 150 bets places?

What's the odds this is chance (assume 50/50 odds for each bet) vs skill (bettor has an edge somehow)?

Thank you



I believe 1 SD is $7072.

After that many bets (150) and betting $550 a game ($550*150 = $82,500), your EV is -$3,750.

Being up $5,000 would mean you're up $8,750 from EV. That's about 1.23 SD's. Putting the odds of this being chance around 10% or so.


That's assuming I did my math right.
"should of played 'Go Fish' today ya peasant" -typoontrav
bazooooka
bazooooka
Joined: Nov 21, 2016
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April 14th, 2017 at 6:53:58 PM permalink
Thank you. Sounds about right to me. How many bets (roughly) till one would concludes that "chance" is down to near 1% assuming the same win percentage?
mustangsally
mustangsally
Joined: Mar 29, 2011
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April 15th, 2017 at 9:06:43 AM permalink
Quote: bazooooka

What if it took 1500 bets instead of the 150 would that imply skill (albeit very slight) since one is only getting 10 units of profit after 1500 bets? Or would a good run last this long?

good question, imo
Quote: bazooooka

At some point things head to 50/50 and the vig crushes you but when can we see if it's skill vs luck.

I say 1500 is a small sample size

I get, using Excel,
at 1500 bets

1 in 30 would still be showing a profit of at least $272.73
ands
1 in 55 would still be showing a profit of at least $5,045.45

some by just luck (I am lucky) would be winning even more
thinking it was more than luck, of course.



Sally
I Heart Vi Hart

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