Monday, January 7, 2013
One of the hardest things for many people to grasp about money and governments (and the relations between them) is that it really just is all made up: it's people keeping track of who owes what to whom. Nothing has intrinsic monetary value. It makes for a lot of mistakes in economic planning and fiscal policy. If the government is in debt, it just needs to be credible in saying that someday it will pay itself back and there will be no problems. That's really it.
In the news release announcing his bill to derail the platinum coin effort, Republican Representative Greg Walden says something really stupid: “My wife and I have owned and operated a small business since 1986. When it came time to pay the bills, we couldn’t just mint a coin to create more money out of thin air.
Sunday, January 6, 2013
Thursday, January 3, 2013
You do the math.
Voxel Based Morphometry (VBM) is a way of analyzing brain scans to detect structural differences. It's most commonly used to compare groups of brains to find average differences, but some neuroscientists have started using VBM to check for abnormalities in a single brain. Scarpazza et al list 34 pieces of research about that, including 13 since 2010.
So it would suck if there were a problem with individual VBM... but there is...
The authors took 200 normal brains and compared each one of them in turn to a control group of 16 normal brains. Because all of them were healthy, the comparisons ought to show no significant differences.
The technique was set up so that, in theory, only 5% of the brains should have been wrongly labelled as containing an abnormality. But in fact, a full 93.5% of the normal brains gave at least one false positive.
So 5% is more like the rate of not being wrong. Oops.