Excellent graphic below from Vizual Statistix showing the average percentage of wagered money won by a casino on games in Vegas. For example, it shows that the house wins about 11% of the wagered money on blackjack, so if you put down $100 at a table the statistics show that the house will collect $11 of that money on average. Other popular games are craps (14%), roulette (17%), and baccarat (14%). Enjoy playing 3 card poker? The house takes over 30% of what is waged! Incredible. Their biggest winner comes from sports betting parlays at close to 40%.
I read an article earlier this week on the part of the brain that makes gamblers believe they have a "hot hand" or something other than statistical probability that will change the outcome of their next bet. The same process is involved with stock market participants who believe they can time the market based on the "feel" of what is coming next on the ticker.
Vegas studies always provide an excellent microcosm of the stock market which is the largest casino in the world and driven by irrational human psychology.
It may be tough to read the graph below even after clicking on it. Click here (and keep clicking on the graph) for the best zoomed in view.