Archive for July 28th, 2009|Daily archive page

How “normal” is Normal Distribution?

With so much talk in the past half-decade about “the Long Tail” it got me thinking about that other popular curve, “the bell curve”. In school, some classes were graded on a bell curve in order to “normalize” the marks across the student body, afterall, it’s called “normal distribution”.

But after seeing so much of the power law distribution long tail in action, from Pareto’s findings to countless examples in biology and physics, I’m wondering if grading according to the bell curve is more rooted in our sense of “fairness” than in reality. I’m sure there’s a sound statistical reason for it and I invite anyone to illuminate that for me.

In the meantime, I’m asking myself: Is normal distribution really normal?