Cause and Effect

Dean Dad asks

Why do so many states require only two years of math in high school?

[…]

We have anecdotal evidence that suggests that students who actually take math for all four years of high school do better in math here than those who don’t. We also have anecdotal evidence that bears crap in the woods. Why the hell do the high schools only require two years of math?

And there is followup at Uncertain Principles

There is a lot of discussion, so I may have missed someone raising the following point:

People who take four years of math and do well are probably good at math. Whatever distribution of students took the math for two years, I’d bet that it’s not the same as the distribution who took it for four. I’ll bet the players who go out for (pick your sport) do better at that sport in gym than the players that don’t, because you tend not to pursue and enjoy an activity if you suck at it.

The discussion seems to be dealing more with the other reasons why schools don’t require four years of math. I can ignore that for a moment and still assume an ideal case not limited by the availability of teachers or caused by bureaucracy. To me, the proposed solution embedded in the rhetorical question is not the head-slap obvious conclusion.

Blackbird Singing in the Dead of Night

The Ultimate Spy Plane

One nit:

Created as the ultimate spy plane, the SR-71, which first took to the air in December 1964, flew reconnaissance missions until 1990, capable of hurtling along at more than Mach 3, about 2,280 miles per hour—faster than a rifle bullet—at 85,000 feet, or 16 miles above the earth. It is the fastest jet-powered airplane ever built.

Mach 3 is about 2280 mph … at sea level. But it varies with density altitude, so at 85,000 feet, it’s about 2000 mph. The speed of sound, i.e. Mach 1, is not a constant of nature — it’s defined by the conditions (as opposed to the speed of light, which is c in a vacuum)