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WARNING: If the dutch book % of the selections approaches 100% then stakes can get very large.
We want a certain fixed profit if any of the horses win. That is what this stake is about.
So say we want a Set Profit = £10
We calculate as per 2) below. We know total probability so we calculate Turnover = (Set Profit x 100)/ total probability
Then the stake for each horse = turnover/odds, so which ever horse wins gives us a return of £10 or which ever profit is set.
1) The formula is based on the fair bet percentage of 100%. For instance, we wish to back three runners in a field of six with the respective odds of 9/4, 3/1 and 8/1 (3.25, 4.00 and 9.00).
Look up the decimal probability values and you will see that these odds equate to decimal values of 30.8% (9/4-3.25), 25.0% (3/1-4.00) and 11.1% (8/1-9.00).
Add these figures up and we get 66.9%.
Thus our profit margin is 100 less 66.9 (100-66.9=) which gives us 33.1%. This is our profit margin.
2) Next we must equate these decimal probability figures to stakes. So multiply the profit required by 100 (fair bet percentage) and divide by the profit margin, in this case 33.1
£10 (profit required) x 100 (fair bet percentage)/33.1
This gives us a figure of 30.21 which is the turnover.
Now, we know that the respective decimal probabilities were 30.8, 25.0 and 11.1; so next we must multiply the turnover amount by each decimal probability to get the required stake.
30.8% x 30.21=9.30
25.0% x 30.21=7.55
11.1% x 30.21=3.35
So, the respective stakes at the odds given (rounded up for ease of use) are as follows
£9.30 @ 9/4 or 3.25 Win returns: £30.23 Profit: £10.21
£7.55 @ 3/1 or 4.00 Win returns: £30.20 Profit: £10.18
£3.35 @ 8/1 or 9.00 Win returns: £30.15 Profit: £10.13
Total Outlay: £20.00 Min Profit: £10.00
The max dutch book % is simply the probabilities of the selections you are dutching added up. So you can limit the total odds of the group of selections you bet on.
In the above example the max book would be 30.8% + 25% + 11.1% = 66.9%, so the max book would allow the bet. If the Max dutch book % was set at 65% then the bet would not go on.
The same applies to min dutch book filter.
You can also apply recovery to the dutching stakes. Just tick the recovery tick box, set the number of cycles, the % to recover of the loss and the action to stop or reset when the number of cycles or additional attempts at recovery
have been met.
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