That headline's right up there with "Dog Bites Man" for shock value, but the Daily Express in the UK isn't one to let mere probability stand in the way of a sensational headline like "Mum beats odds of 50 million to one to have 3 babies on same date". As Ben Goldacre helpfully explains, the probability is actually a modest 133,000-to-one (50M-to-one is the probability of having four babies all on the same date, or three babies all on a prespecified date). The article was published over a week ago, but there's no correction in the online content, other than a comment from an observant reader. Another one for the "Film at 11" vault, like the Bulgarian Lottery coincidence.
Bad Science: Guns don’t kill people, puppies do
Aren't the odds even better? Maybe something like 90^2:1? There are things you can do to significantly improve chances of pregnancy. Storks don't deliver babies.
Posted by: Richard | February 19, 2010 at 08:50
I've always enjoyed the rather trickier "probability of finding 2 or more people with same birth date in a group of X people."
Ever since I saw it worked out in h.s. math class. The teacher called it a good way to take suckers' money. In a room filled with, say, 50 beered-up people (preferably not friends of you or your significant other), offer to bet anyone and everyone who'll take you up on it that 2 among them share a birth date (not same year). It's a sure winner.
Posted by: Jon Jacobs | February 19, 2010 at 09:28