This is the short edition of Morales.

First broadcast on the BBC World Service.

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Hello and welcome to Morales on the BBC World Service.

You can insert your own statistical pun here.

I'm Tim Halford.

A little later we'll be investigating what we can learn by examining the birthdays of World Cup footballers.

The birthday paradox is probably one of math's greatest hits.

It's something you can say in one line which gives you this kind of wow.

But first, I'd like to claim that the world's most popular economics writer is me.

But sadly, we don't live in a just universe.

Instead, it's Steve Levitt, prize-winning professor of economics at Chicago,

famous data detective and with the journalist Stephen Dubner,

the author of Freakonomics and more recently think like a freak.

Levitt and Dubner say they want to help people make better decisions.

So I sat down with Steve Levitt and asked him about a very unusual project he and Dubner have been working on.

Essentially, we put out the word that if you had a big problem that you were trying to solve,

you could come and we would help you.

We would help you decide whether you should get a tattoo or go on a diet or quit your job

or break up with your boyfriend.

...