I believe the worst damage to statistics is specious reasoning. My favourite chocolate promotion is Mars' '1 in 6 Wins a Free Bar' (on currently here in Oz). If I buy 6 bars, most people would assume I would win once. In fact, I have only a 2/3 chance of winning a free one
1 - (5^6/6^6)
Buy 12 bars, and there's still a more than 10% chance I won't have won yet...most of the chocolate-buying government-voting lottery-praying public would be stunned.
Although the average number of bars you'd need to buy before you win is indeed six. I think almost no one would put the odds of actually winning one by buying six at 100%.
1 - (5^6/6^6)
Buy 12 bars, and there's still a more than 10% chance I won't have won yet...most of the chocolate-buying government-voting lottery-praying public would be stunned.