Twins, or In which newspapers mess up odds calculations (again)

This BBC piece interviews a couple who've been 'blessed' with three sets of twins (rather you than me).   The caption states that

Doctors told them the chances of having three sets of twins was 500,000-1.

Doctors that don't know much about genetics, perhaps.

Horse Racing and Coincidence

Just penned this to the BBC about why their piece on a jockey winning seven races in a single day quotes the wrong odds.

In your article on Richard Hughes winning seven races in a single day, you quote the odds of this event as being 10,168-1.  Whilst undoubtedly a fantastic achievement, these odds are incorrect, since they they ignore the fact that Mr Hughes raced in eight races that day.  The chances of him winning 7 out of 8 races (or more) is about 1,257-1, which is a bit more modest.  In particular, it seems fairly unlikely that someone would place a bet on the rider winning these particular seven races, and not the eighth.

How should statistics be taught? Some thoughts.

Inspired by Timothy Gowers' recent post on how mathematics should be taught to non-mathematicians, I thought it might be prudent to ask how statistics should be taught.  If you need to be motivated as to how important teaching statistics is, watch Arthur Benjamin's short TED talk.

What is probability?

I haven't seen any particularly interesting (or unusually egregious) uses of statistics in the last few days, so it's time to have a more philosophical outing.  Of course, if you see anything in the news you think is worthy of a post, email me (evans [at] stats [dot] ox [dot] ac [dot] uk).

So to the title of the post - what is probability?  Probability can be viewed as just a mathematical construct, which we'll explore some other time, but even with the mathematical rules in place, there are various interpretations of what a probability actually is.  At school we usually think about rolling dice and flipping coins, so let's start there.  I flip a 50p coin: what's the probability that it comes up heads?  You'd probably [sorry] say it's 'evens', 'a half', 'fifty-fifty', or (as mathematicians generally prefer), '0.5'.