Gelman galore

Clearing Out My Closet season continues, this time with a number of interesting posts from Andrew Gelman:

Uh.. Um..
I [Mark Liberman] took a quick look at demographic variation in the frequency of the filled pauses conventionally written as “uh” and “um”.

Marginal vs marginal
To me, the most interesting bit of terminological confusion is that the word “marginal” has opposite meanings in statistics and economics. In statistics, the margin (as in “marginal distribution”) is the average or, in mathematical terms, the integral. In economics, the margin (as in “marginal cost”) is the change or, in mathematical terms, the derivative.

If you are jumpy, you are less likely to be liberal
In a group of 46 adult participants with strong political beliefs, individuals with measurably lower physical sensitivities to sudden noises and threatening visual images were more likely to support foreign aid, liberal immigration policies, pacifism, and gun control, whereas individuals displaying measurably higher physiological reactions to those same stimuli were more likely to favor defense spending, capital punishment, patriotism, and the Iraq War.

Friday the 13th, unlucky?
A study published on Thursday by the Dutch Centre for Insurance Statistics (CVS) showed that fewer accidents and reports of fire and theft occur when the 13th of the month falls on a Friday than on other Fridays. . . . In the last two years, Dutch insurers received reports of an average 7,800 traffic accidents each Friday, the CVS study said. But the average figure when the 13th fell on a Friday was just 7,500.

Datacharmer recently made a good comment on this:

Apart from avoiding risky behaviour on Friday the 13th because it is deemed unlucky (which might well be happening), you should also consider that Friday the 13th – unlike other Fridays – CAN’T be Christmas or New Year’s (where people get drunk and drive), and it will also be associated with a lower (or higher) probability of falling before a bank holiday weekend (or I guess in the States Independence day, etc).

I guess all I’m saying that it could well be other factors driving this result other than a change in people’s behaviour because Friday the 13th is ‘unlucky’.

How about accidents on Friday the 12th of Friday the 14th? The article only compares Friday the 13th with an average Friday – in fact, it doesn’t even reveal whether the 13th is least accident prone Friday in the book…

by datacharmer | Sunday, January 22, 2012
  | | Gelman galore @bluematterblogtwitter