February 19, 2012: Lucky? -Do the math.

Being Presidents Day Weekend, my sister and I scheduled our annual getaway to Atlantic City. This year we invited our fabulous friends for our spa getaway. We stayed at the Borgata, enjoyed the spa all day, went to dinner and then... not being a gambler myself, I watched my friend play roulette. Gambling just never appealed to me and definitely never made sense to me.  You just put your money out there and have no control over what happens... yikes. My friend, on the other hand, has always been lucky. I distinctly remember going to visit her in NYC after we graduated from college. She met me in Penn Station and we went to grab a sandwich at Subway... as the man was making our sandwiches she was making small talk and announced that it was her birthday. Next thing I know we are both getting free meals. Hmmm. Now I know you must be thinking that there are "other factors" that come into play here and yes... I know. The thing is that this is a regular occurrence for her. She literally wins stuff or gets free stuff all of the time and has since we were little. So, naturally, standing at the roulette table with her was entertaining. She was confident and said to me "I am going to win like $400 and then we can leave." She basically planned on winning all of the money that it cost to be there for the weekend. I didn't even question her, I knew she would win. After pocketing $400... she called it a night.

So this experience led me to question WHY she was able to do this so easily. It's just luck right? This question bothered me. People seem to be thinking, reasoning, problem solving when around the roulette table. Perhaps they are considering laws of probability... for example... if black was hit 5x in a row, perhaps I should bet on red... because black is unlikely to hit 6x in a row. Hmmm... this reminded me of probability in genetics. When I teach genetics we work with probability. Punnett squares are used to determine the probable genetic outcomes of a mated pair's offspring. In a simple monohybrid cross, the Punnett square will show 4 genetic possibilities in the offspring. My students often have trouble understanding the difference between absolute and sequential probability (and I had a difficult time explaining it until I looked this up!!). A Punnet square shows absolute probability. So, for example each time a couple conceives they have a 50/50 chance of having a boy/girl. Check out this example (that I got from a roulette site!). So let's say you walk up to a roulette table and the number 8 has hit 4x in a row (highly unlikely). Would you bet on 8? Your answer depend on your understanding of absolute vs. sequential probability.

It turns out that the word roulette is french for "little wheel." The roulette wheel was actually introduced by French mathematician and physicist Blaise Pascal in the 17th Century as part of his search for a perpetual motion machine. (math, science, history, world languages... all in a quest to learn about roulette!)

So after much investigation, I think there are definite strategies that might make her better at winning... but luck plays a part. Regardless, understanding probability will help you avoid making bets based on incorrect thoughts about sequential probability. 

Take the roulette QUIZ.