Impromptu Public Speaking

Not much to tell. Dr. N has officially run out of material in Intro Probability -- the rest of the year will be spent reviewing old material. Better make sure I have my caffeine ready.

We had an impromptu five-minute quiz and Dr. N asked someone in the class to present a solution. I decided to, since if I'm going to be doing this for a living, I'd better start feeling comfortable doing it. I'm really not that uncomfortable -- I taught in a classroom setting for three years at a major university during an aborted attempt at a post-grad mathematics degree -- but the hard part is explaining things clearly.

Here's the question:

"Assume you draw 13 cards out of a standard deck, without replacement. Given that you have drawn at least two kings, what is the probability that you have drawn at least three kings?"

As for Dr. S's class, all kinds of weird stuff involving the "Rao-Blackwell Theorem", which is

E(X) = E[E(X|Y)]

Var(X) = E[Var(X|Y)] + Var(E(X|Y))

I'm writing this entirely from memory, so if the theory I wrote is wrong, it's wrong. He derived it in class but it was a very confusing explanation. We did a few problems from his problem set due Friday, so it was just watching him talk.

After class, a student asked me for some study help. I'll be meeting with her Friday. I had met with her a couple of times in the summer to help with Multivariate Calculus, but she stopped showing up. So I have some misgivings, but, it looks I'm just a soft touch. (Insert laughter here.)