Thursday, November 27, 2008

Independence vs. Correlation

I wonder, of the many distinctions made between these statistical notions whether the following interesting one has been made, i.e., to declare two random variables independent, an observer is not required, whereas only an observer can pronounce two random variables as correlated, post-hoc. Hence, independence is a property of the distribution, (in the context of generative function as opposed to histogram), whereas correlation is a property of one single realization sampled from that distribution with respect to another such realization.

If I were Hugh Macleod, I would say at this point, "Exactly. Bayesian vs. Frequentist."

Wednesday, November 5, 2008

Vetri kodi kattu

I walked into the bus with a textbook and a take-away snack, my usual brooding self, and proceeded towards a seat. Instead of the normally indifferent or imperceptible nod from the bus driver, I received an animated "tervetuloa" and a broad smile. He was black. Listening to his own radio catching a bit of the victory speech. Obama trickle-down effect WIN? I tried to find a seat in front to eavesdrop. For the rest of the people on the bus it was another day in the works.