Are you a rotten gambler or just plain unlucky? You seem to have hit on a winning system when woe and behold you are struck down by a really bad losing run and with it your confidence. So, were you just unlucky?

If you know the probability of an event and how many times you will perform the event there is a formula that will work out your maximum winning and losing runs.

Let us assume that S=The number of times you play this game / perform the event. In this case a coin toss. S=555 coin tosses. For success in this trial we will need to throw a head. There are only two events so our chance of success is 1/2 or 50%

Fire up Excel and type the following formula

=ROUND(LN(555)/-LN((1-0.50)),0)

= 9

In 550 throws you will get a maximum run of nine heads in a row.

You could of course work out the maximum run of losers which, as this is a 50/50 chance, is exactly the same. Try varying the % figure (0.50) to see the effect of a better or worse strike rate. If you are confident that you know the % success of the event this is a good calculation for working helping out how much bank size you could stake. I have done lots of work on this subject but far too much and too complex to post here.