(no subject)

I don't know if no-one knows, or if no-one cares because nobody's died (yet), but hundreds of square kilometres of England are currently under several feet of water. Vast swathes of it, enough to swamp about 10 to 15 copies of New Orleans. Luckily the population isn't anywhere near so dense in these areas. Watching the aerial footage taken from news helicopters makes it look like a completely different landscape. Some of you History-types will be appalled to hear that the water seems to be seeping into 12th century Tewkesbury Abbey - I wonder how much damage that will do, and if it's happened before in the last 800 years. You'd think so, wouldn't you?

I don't have any sort of point to make really, but I do find it fascinating. It's like the natural disaster nobody wants to acknowledge. Floods are a bit boring, compared to hurricanes, tornados, or earthquakes. But for those whose cars are stranded on newly formed islands, or those who haven't been home for several days, or those who have no drinking water, or electricity, it's just as bad.

crap statistics

'One in five young teenagers say that their friends are carrying knives and weapons, says a major annual survey of schoolchildren's health and wellbeing', apparently.

Sounds unpleasant, right? Except there's a clear difference between 1 in 5 people carrying weapons and 1 in 5 people having a friend that carries weapons.

Let's assume that everybody is telling the truth, and that friendship is reciprocal. Let's also assume that someone who carries a weapon but has no friends who do, will report that they know nobody who carries one. If each person interviewed has just 1 friend, each pairing being different, then yes, 1 in 5 people carry weapons. But if you take a more reasonable estimate of how many friends a person has, the values change a lot. Imagine 10 children, all friends with each other. Therefore each has 9 chances of knowing a friend who has a weapon. All it takes is one of them to have a knife, and then suddenly each of them knows someone with a weapon, making the stats 9 out of 10, not 1 in 5. To scale it down to the stated 1 in 5 would require something like another 4 groups of 10 friends, each with no weapons, making it closer to one person in fifty carrying a weapon.

It follows that the ratio of "friends with weapons" to "people with weapons" is proportional to "friends of people". If you have an average of 10 friends, then it stands to reason that you're ten times as likely to know someone who carries a weapon, or someone who lives in a house with a green door, or someone who knows pi to 14 decimal places. But it could be even more misleading than that; if you consider that the petty thugs with their knives are often well-known and the geeky misfits have fewer friends, it makes the proportion of people who know the weapon-carrier even higher by comparison, and thus the proportion of people who actually carry weapons far smaller.