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March 2nd, 2017 at 11:51:59 PM
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Hi, I already know the probability of losing X number of coin tosses in a row (50% for 1 flip, 25% for 2 flips, etc.).

Can someone tell me the formula of losing X number of coin tosses in a row, WITHOUT winning two in a row (instead of only one)?

To clarify my question, there is this negative progression which goes like this:

1,1,1,2,2,3,4,5,7

If this bet is won at ANY point, parlay it and wager both bet and win, or two units. If this wins, start from the beginning.

Example:

Bet A (1check): lost

Bet B (1check): lost

Bet C (1check): lost

Bet D (2checks): won

Bet E parlay (2 checks plus the 2 checks just won): won.

You're now ahead by two checks.

I would like to know the odds (probability) of going from 2 flips to 50 flips WITHOUT winning two in a row. All I need is the formula and I could work it out. But if anyone has a chart, that will be fine also.

Thanks for your help!

Can someone tell me the formula of losing X number of coin tosses in a row, WITHOUT winning two in a row (instead of only one)?

To clarify my question, there is this negative progression which goes like this:

1,1,1,2,2,3,4,5,7

If this bet is won at ANY point, parlay it and wager both bet and win, or two units. If this wins, start from the beginning.

Example:

Bet A (1check): lost

Bet B (1check): lost

Bet C (1check): lost

Bet D (2checks): won

Bet E parlay (2 checks plus the 2 checks just won): won.

You're now ahead by two checks.

I would like to know the odds (probability) of going from 2 flips to 50 flips WITHOUT winning two in a row. All I need is the formula and I could work it out. But if anyone has a chart, that will be fine also.

Thanks for your help!

March 3rd, 2017 at 1:27:56 AM
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It's the same. Flipping a coin:

TTTT is the same as TTHH which is same as THTH or HHHH or TTTH or THTT etc. I can't think of a general formula for what you're looking for, other than if you do X flips, there'll be 2^X possible sequences and each will have probability 0.5^X.

I'm sure someone like TheDonGuy will come up with some super simple formula. :(

TTTT is the same as TTHH which is same as THTH or HHHH or TTTH or THTT etc. I can't think of a general formula for what you're looking for, other than if you do X flips, there'll be 2^X possible sequences and each will have probability 0.5^X.

I'm sure someone like TheDonGuy will come up with some super simple formula. :(

March 3rd, 2017 at 6:19:20 AM
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Fibonacci numbers work great when the probability of success AND failure are 50% exactly.Quote:TERMINATORI would like to know the odds (probability) of going from 2 flips to 50 flips WITHOUT winning two in a row. All I need is the formula and I could work it out. But if anyone has a chart, that will be fine also.

Thanks for your help!

this will help out:

Fibonacci numbers streaks

for any other probability use a spreadsheet like this one

my Excel in Google

https://goo.gl/Af59ca

it is for a run of 2 in a row

so make a column and subtract the values from 1

thank you for sharing

Sally

Last edited by: mustangsally on Mar 3, 2017

I Heart Vi Hart

March 3rd, 2017 at 7:15:38 AM
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Thank you, Sally. This is what I was looking for!

March 3rd, 2017 at 8:04:54 AM
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I think I disagree with your 2 check net profit.Quote:TERMINATORExample:

Bet A (1check): lost

Bet B (1check): lost

Bet C (1check): lost

Bet D (2checks): won

Bet E parlay (2 checks plus the 2 checks just won): won.

You're now ahead by two checks.

after betC, profit = -3

bet D wins at 2 so 4 total for next bet

4 wins for 8 total, but profit = 8-2 or 6

6 + -3 = 3 total profit for the parlay win

unless there is a tip in there I did not see

looks fun to play at Craps dpass

more thrills than flat betting

I would say

good luck

Sally

I Heart Vi Hart

March 3rd, 2017 at 9:38:49 AM
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Yes, you are correct, it is 3 units profit. I was in error. Thanks for pointing that out!