Extreme Comparisons

This is just a fairly short note on what has been covered in other cases elsewhere.  The BBC reported today that Tameside in Greater Manchester is the "UK's heart disease capital".  This is on the basis that the rate of deaths from heart disease between 2009 and 2011 was higher than anywhere else, at 132 per 100,000 people.  The data come from the British Heart Foundation, and I couldn't immediately see how to get at it.

The article mades a particular point of noting that this rate is three times higher than that of Kensington and Chelsea.  This sounds very dramatic, but it really isn't, so don't go moving just yet (even if you can afford a house in Kensington).

Smoking rates: even the 'good guys' shouldn't be trusted

The Guardian reports today that the number of children under 16 (more precisely aged 11-15) taking up smoking has has risen by 50,000 in a single year.  This is a slightly irritating headline simply because the number is without context, but the sub-headline is more helpful: from 157,000 to 207,000, which is quite dramatic: a 32% increase.

First obvious question - is this statistically significant? Well, let's have a look at the research quoted by the Guardian, which comes from Cancer Research UK.  Their Figure 6.10 immediately arouses suspicion.  There does appear to be an uptick in the figures from 2010 to 2011, but they remain below the 2009 figure!  The overall trend in the numbers over the past 10 years is clearly downwards.  So either we believe that the number of children taking up smoking fell and then rose dramatically in consecutive years, or else we might just be witnessing a bit of noise in our data.

Independence, independence, independence

Multiplying probabilities without any thought is a dangerous game.  Just look at this piece in Rolling Stone, referenced in this Guardian article.

...warmest May on record for the Northern Hemisphere – the 327th consecutive month in which the temperature of the entire globe exceeded the 20th-century average, the odds of which occurring by simple chance were $3.7 \times 10^{-99}$, a number considerably larger than the number of stars in the universe.

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.

Fruit, Vegetables, Health and Happiness

Whilst perusing the Daily Mail today (my excuse is that it's next to the espresso machine) I saw this interesting health advice:

Forget five a day: Now scientists say you'll be healthier and happier eating seven daily portions of fruit and veg.

The phrase "scientists say" is always a red light. 

Trust your instincts

As Obi Wan almost said: "Let go your conscious self and act on instinct.  Your news articles, government agencies and other organisations can deceive you, don't trust them."

My brother Andrew (@andysstudy) has been studiously following this advice since 1977, and sent me this tweet:

See below. There are 73m children (u15) in EU I find it hard to believe 1:73 goes missing every year? http://www.euronews.com/2012/10/01/has-anyone-seen-my-child/

Road safety - how not to reason from data

My apologies for going quiet over the summer.  I've been in China, and they're not too big on blogs there (blogger is blocked).

Just a short post here, on something fairly obvious.  Here's an extract from post number 51 by Cambridge News' Cycling Blog on speed limits.

In Great Britian in 2011, 7 people were killed on a road with a 20 mph limit. 636 killed in a 30 mph limit. 289 people were seriously injured in a 20 mph limit, 13,168 in a 30 mph limit... Yes, these are large numbers. But it is the proportions that matter here... So that is proof then. Lower speed limits means fewer people killed.

[In case you're wondering, there's no irony in the last sentence.  At all.]  I assume you're all thinking the same as me by now.