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odds and such
this is messing me up a little....
if i take an even money bet 10k+ times but walk away from the bet each time i am ahead...can i make a profit.......
if i take an even money bet 10k+ times but walk away from the bet each time i am ahead...can i make a profit.......
Comments
Are you asking if even money bets are +EV?
After the bet is resolved????
i can't ask the question properly.....like say flipping a coin pays you 1 bux for every time you guess correct and it cost .50 to play.
you play 3 times and your up 50 cents so you quit......
then you come back and play 10 times and your down a dollar, so keep playing till your even and then play more until your up 50 and then you quit
your up a dollar now
oh my lord what is wrong with me.....
im super strong in math but odds and stuff i never understood.
You are flipping a coin against another player. After every flip you get to decide whether to flip again for double or nothing, or to quit.
According to the strategy, whenever you win a flip, you force an end to that session. If it is the first flip of a session then you win 1 unit. Otherwise you come out even.
The problem with this theory is that you would need an infinite bankroll to make it work, since if you have a finite bankroll you will eventually go broke when you cannot cover a string of bad double or nothing tosses.
I don't think this is what he is asking -- btw this is a basic blackjack strategy used by some pros.
I think he is asking this without the double of nothing option -- he just gets to decide to quit if he gets ahead.
Are they US or CDN coins?
What is the exchange rate at the time?
You flip a coin between one an 10.000 times (let's say 9999 times just because). If you flip until you've flipped 9999 times the probability that you're ahead is P(profit | 9999 flips)=50% and the probability that you're down is also 50% so if we flip it out it's not +EV as expected.
Furthermore if we repeat the 9999 flip set infinate times and plot a graph with the net gain/loss on the x axis and the percentage we got that net gain/loss on the y axis we would be plotting a standard normal distrubution curve.
(only with different x and y scales as well as the top of that bell shaped thing intersecting the y axis)
If we cut the flippage as soon as we get ahead the first half of the curve will remain close to the same except we move the vertex quite a bit down the y axis but we basically let the y axis cut the shape in half and replace the right hand side of it with a single point on the graph located at P(X=0.5, Y=a big %) since we're gonna profit most of the times.
Now this is a part I can't prove but I suspect that the integral of the positive x values will be equal in magnitude to the integral of the negative x values meaning that even this will be breakeven. So to answer the original question I'd have to say no, it's not +EV but it's gonna be really low varience until the system valuerapes you (much like the bet one unit, try to double up, if fail bet two units, if fail bet 4 units until win)
Edit: Feel free to correct me, I've been wrong before
Only works on infinate bankrolls.
http://en.wikipedia.org/wiki/Martingale_(betting_system)
heh looks like boobie
k just to clarify though, because you ending statement made me unsure
you bet 10,000 times and you break even....but on the 10,001 time you are up .25 cents
you walk away.......
you come back tommorow and bet 30k times you are down .25 you play 10k more times you come back to even but you play 20k more times you are up .25 on the day....so you are up .50 cents altogether....
in other words on a break even bet that you can make 30k+ times a day can you make money over a year if you quit each day when you are ahead.
..............................
okay maybe the answer is this is gambling......you can make millions on it but the odds against making money are astronomical..........meaning you have to play so much, but it doesn't effect your bankroll unlike what wett's posted.........
you will eat this post!!!
sorry, not hungry...