A point of pickiness...
Originally Posted by slippahs
Airlines use their historical data and other factors to figure out which flights will have more no-shows. It's this complicated formula that determines the number of seats available to sell on planes. When the formula goes wrong (e.g., less no-shows then previous expected), that's when you find a need for a VDB situation.
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There's nothing wrong with the formula if a flight is oversold. The formula estimates the expected value and variance of the number of people who show up. The only way to guarantee zero no-shows is to never overbook.
Take coin flipping for example. If you flip a fair coin 100 times, the probability of getting more than 60 heads is approximately 1.8%.
So, if you do happen to get 61 heads, it doesn't mean there's something wrong with the coin. It just happens every once in a while.