Saturday, December 6, 2008
Saturday, November 15, 2008
Textbooks versus Packets
I'm planning my courses for next semester. Textbooks cost a lot. Viscusi, Vernon and Harrington's regulation text costs $88, which is typical. Are they worth it? Yes, probably. The cost of me, the professor, and the time cost of the students is much higher, and a good text is valuable. But there is one big problem. Students don't keep their texts. They resell them. This loses them one of the most important parts of their education. If they realized this, they wouldn't sell them, even at the current high prices, but they don't. It might nonetheless be important. If I assign them a packet of readings instead, will they keep the packet? If they do, maybe that is enough of a teaching improvement that I should do it.
Tuesday, November 11, 2008
When Does Human Life Begin?
A hard puzzle in abortion policy is when "human life begins". Is a one-celled embryo a human? Is an 8-month fetus a human? Is a 2-year-old a human?
How about if we approach the question from the other end. When does human life end? When is someone dead? It could be when his heart stops, but people do get revived often from that state and we don't call it resurrection. It could be when his brain activity stops, and I think that is the common criterion.
If the criterion for lack of life is lack of brain activity, then the one-celled embryo is not alive. Rather, we need to ask when a brain begins, and when it becomes active. A pro-abortion blog that discusses the brain criterion says that brain activity starts much later than the brain itself is formed, at 21 weeks, which is 5 months. The same blog says anti-abortion people claim the time is 10 weeks (which sounds more plausible to me, and even rather late).
November 18. Another approach would be to ask when an embryo has blood. Blood has special significance in the Bible. This webpage doesn't mention blood specifically, but it implies the embryo has blood somewhere in the 8 to 21 day range. There is a brain at 29-35 days, and brain waves at 40 days. In Arizona, at least, in 2007 of 10,486 abortions, 3,032 were at 6 weeks (42 days) or less. 102 were at 21 weeks or more.
Monday, October 20, 2008
Tuesday, June 10, 2008
Male and Female Majors at Yale
Wednesday, February 13, 2008
It is salutary to keep in mind that in many past cases where data conflicted with robust modeling results, it turned out to be the models that were right and the data that was wrong. This was the case for the early satellite reconstructions of twentieth century lower tropospheric temperature, which showed a spurious cooling. It was also the case for early reconstructions of tropical climate during the Last Glacial Maximum, which failed to show the cooling we now know to prevail in that region during glacial times.
Thursday, January 10, 2008
Wednesday, January 2, 2008
Sunday, November 18, 2007
working. You may not be able to fix the degree of your belief, and without a strong belief you may find the discipline of following it hard, but you can make the decision.
Wednesday, November 14, 2007
There is an inconvenience which attends all abstruse reasoning, that it may silence, without convincing an antagonist, and requires the same intense study to make us sensible of its force, that was at first requisite for its invention. When we leave our closet, and engage in the common affairs of life, its conclusions seem to vanish, like the phantoms of the night on the appearance of the morning; and ’tis difficult for us to retain even that conviction, which we had attain’d with difficulty.
Tuesday, October 2, 2007
Bayesian vs. Frequentist Statistical Theory: George and Susan
Susan either likes George or dislikes him. His prior belief is that there is a 50% chance that she likes him. He also believes that if she does, there is an 80% chance she will smile at him, and if she does not, there is a 60% chance. She smiles at him. What should he think of that?
The Frequentist approach says that George should choose the answer which has the greatest likelihood given the data, and so he should believe that she likes him.Click here to read more