# Help us, Phil Plait, you're our only hope!

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This little gem of a press release was picked up by Reuters a couple of days ago - I’ve only just now had time to post it, though, because I’ve been busy rashly betting on five-foot-six Swedes in the high jump. You can almost feel the waves of stupid emanating from the screen:

*Forget training, dedication and determination. An athlete’s star sign could be the secret to Olympic gold.*

Help us, Phil Plait, you’re our only hope!

*After comparing the birthdates of every Olympic winner since the modern Games began in 1896, British statistician Kenneth Mitchell discovered gold medals really are written in the stars. He found athletes born in certain months were more likely to thrive in particular events.*

Now, I’ve had a rummage around on this dude’s website, and I can’t find any actual data. Lots of pretty charts, but no data that we can use to replicate his findings.

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Mitchell dubbed the phenomenon “The Pisces Effect” (pisces is Latin for fish) after finding that athletes born under the sign received around 30 percent more medals than any other star sign in events like swimming and water polo._

I suppose at this point it’d be uncharitable to point out that horoscopes were invented three thousand years ago? And since then, the precession of the equinoxes means that on the traditional “Aries” dates, the sun is actually in Pisces?

*For fencers looking to deliver a sting in the tail and make it to the podium, Scorpio is the right sign. Two of the three Beijing medallists in the men’s individual sabre event were Scorpio, he said.*

Now, this is a great example of what this bloke is actually doing: he’s taking a huge pile of data, picking out “interesting” points, and disregarding anything that doesn’t prove his theory. In the press release, he says that “historically, Scorpios – the star sign with a sting in its tail – have excelled in Olympic sabre fencing competitions”.

No explanation of why Scorpios aren’t any good at epee or foil fencing.

The release also says that “in 2008, two out of the three medallists in the men’s individual sabre event were Scorpio. The odds of this result are one in 2,000”.

This is cherrypicking. There are twelve events he could’ve picked - men’s and women’s; team and individual; epee, foil and sabre. If one of those events gives him the result he wants, that’s what he’ll cite.

Also, even if his premise is right, his math is wrong: the per-event odds are one in fifty. **If he can’t get that right, how can we trust the rest of his statistics?

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For the rest of the gory maths, hit the “Read More” link.

*For pole vaulters charging down the track, it is better to be born under Taurus, the sign of the bull.*

Now… last I checked, pole vaulting involved a lot more jumping than running. Wouldn’t you expect successful pole vaulters to be born under the Chinese sign of the rabbit, instead? After all, if we’re going to give credence to unscientific junk, let’s give equal credence to everyone’s unscientific junk.

_Explaining his eureka moment with all the zeal of a statistical crusader, he concluded: “Did you know that the distribution of Olympic swimming medallists against the tropical astrological zodiac signs can be almost exactly mapped by a polynomial function of the third degree? That’s one to shut people up at a pub.”

_

Since this is a family friendly blog, I won’t say what I’m thinking. Suffice to say, nine letters, ends with T, begins with H-O-R-S-E-S-H-I. Cryptic crossword fans, have at it.

Shame, Reuters, shame.

Okay… what are the odds of at least one of the six individual fencing events having at least two of its three medalists be Scorpios? Let’s leave out the team events - with four people on a fencing team, and so twelve medallists in each of six categories, it’s too damn easy to find enough Scorpios to sound interesting.

**Warning: math starts here.**

Now… if we assume the probability of a person having a given star sign is always ^{1}⁄_{12} (it’s not quite, but it’s close enough for government work), this reduces to a version of the birthday problem with only twelve birthdays.

The odds of none of three people having the same star sign are, therefore, 1*(1- ^{1}⁄_{12})*(1-

^{2}⁄

_{12}) = 76%. The odds of at least two people having the same star sign are, then, 100%-76%=24%, and the odds of them both being Scorpios are one-twelfth of that, or two percent. Note that this is not equal to one-in-two-thousand, as the guy claims - it’s one in fifty.

Now, there are six individual fencing events. The odds of at least one instance of “two-scorpios” is equal to one minus the odds of *no* “two-scorpios” - or, 0.98 in every event. The odds of no “two-scorpios” in six events, then, is 0.98^6 - about 88.5% - and the odds of at least one “two-scorpios” in the six events are, then, 100%-88.5%, or 11.5%.

So the odds of this wondrous event - a fencing medal ceremony with two Scorpios on the stand - aren’t anywhere near the one-in-two-thousand odds he claims. **They’re more like one in ten.** And with thirty or forty different events at the Olympics to pick from, this guy won’t have *any* trouble finding some events that fit his pet theory.