Monday, December 26, 2005

Lying With Statistics

I haven't yet thought of a productive way to say to the students, "Yes, it's true. Professor Euler is a tough grader, and the students in his class do sometimes get lower letter grades than they might were they in a different section. And there is nothing that I am going to do about it." And, while this is true, I'm sure that from time to time Euler ends up with such a group of unprepared and unmotivated students that even the mythologized version of Jaime Escalante would throw up his hands in frustration and find the whole endeavor to be one of frustration and wasted time. And, most importantly, at this point there is no way for me to tell the difference.

And so I find ways to select misleading factoids to calm these upset students. Because I'm not going to ask Euler to apply some renorming transformation to his grades; a difference of opinion on what qualifies as an "excellent" knowledge of the subject does not unfair grades make. And so I point out: Euler gave more As than Gauss. I don't mention that Euler didn't give any Bs.

More disturbing: Professor Pythagoras had some of the highest letter grades, but his students' exam grades were near the bottom of the pile; I wouldn't want his students in my section next semester.