this is not a journal title

I am looking for a reliable source to explain to a non-mathematician why drawing conclusions from a sample size of 3 is ridiculous.

In case you haven't heard,

Pittsburgh Public Schools officials say they want to give struggling children a chance, but the district is raising eyebrows with a policy that sets 50 percent as the minimum score a student can receive for assignments, tests and other work.
...
"The 'E' [failing grade] is to be recorded no lower than a 50 percent, regardless of the actual percent earned. For example, if the student earns a 20 percent on a class assignment, the grade is recorded as a 50 percent," said the memo from Jerri Lippert, the district's executive director of curriculum, instruction and professional development, and Mary VanHorn, a PFT vice president.

--Joe Smydo, Pittsburgh Post-Gazette

It is my understanding from this, that they should not be recording percentages at all, and instead should be transitioning entirely to letter grades or a GPA system. The two systems are not really compatible (despite what all US colleges and universities try to convince us) since they use different scales and ways of averaging.

So in the end I do not see this change as administrators requiring grade inflation. I see it as administrators who do not understanding math/statistics trying (and failing) to come up with a grading system that allows for student improvement.

Only in base 10 though. In base 11 I'm only 28. ;)

With some help from jethereal the other day, and his awesome TI-89, I have solved my commute. The optimal speed for me to drive based upon gas mileage and time spent is 95mph. Since I also want to take into account safety and tickets, this means drive as fast as I feel is safe and won't get me ticketed, so my current trend of going 75ish seems good to me, and I should *not* try to slow down.

( Solution )

The trivial solution is that I can minimize the cost of my trip in terms of both dollars and time if (x=0) I live in my office, or I work from home. A little further exploration showed that v=95 is a local minimum (good) and v=180 is a local maximum (bad). Despite the fact that the faster I drive, the worse my gas mileage, the time savings dominates until I reach 95pmh. At that point the gas mileage is bad enough that it makes the cost worse and worse until I hit 180mph - if I drive faster than that I should start saving money again.

So I think I determined the real reason that some people drive 95 mph on the highway: they're mathematicians!

x-posted to mathsex

Ah, finally it is a comfy 75ºF. I got home around 7pm at 55º, and it's now 12am at 75º, so that's Δ20ºF/5hr = 4º/hr = 1º/15min ... and I could now go on and look at my 2 heaters' wattages and calculate the power that went into the room temperature and figure out how lossy my bedroom is, but I don't feel like it. Yay math! Yay laziness! If anyone else feels like it, go ahead and I'll check your results. :-P