If you spin a coin twice, what is the probability of getting two heads?
So how did the leaders of the nation—the men and women charged with spending our money—fare?
As you can see from the chart above (taken from Mark Easton's blog), most of them got it wrong, with only two out of five getting it right. Seven per cent of them couldn't even muster a guess. Labour MPs were more than twice as useless as the Tories.