Let's play a little game of virtual chance. I toss a virtual coin that you know to be equally likely to come up heads or tails and it comes up heads. I toss it again, it comes up heads. Again, heads. After 8 tosses every one is heads.

The chances of this are one in 256. To toss 9 heads in a row is a 1 in 512 event. So what are the chances of another head being thrown. Well all geekmiesters, like myself, who did probability theory, know it is 1 in 2. Since chance has no memory the previous 8 throws do not affect the chances on this throw.

How many of you could resist betting on tails after such a long run of heads? It is this human flaw that provides casinos with most of their revenue.

One interesting aspect of this phenonemon is the irrational fear of highly unlikely events. We see events that have a high emotive value as more likely than what they are.

Let's take, for example, the terrorist attack in the US on September 11, 2001. This was clearly a very emotional event, not only for the US, but most western countries. Three thousand innocent lives were lost needlessly but has the risk of terrorism increased or decreased because of the attack.

My thinking is that it has probably decreased. Although potential terrorists may be spured on by this success, this is probably more than outweighed by the tightened security measures that have been put in place post-September 11. Because terrorism is more salient these days does not make it more likely. Sadly it has always been around and always will be but you should be more concerned about that MacDonalds hamburger than an Iraqi terrorist. Heart disease from obesity is a far greater killer.