## Happenings – 2011 Jan 15

Well, I’ve managed to put off this post until almost the last minute; but since I did not put out a technical post last Monday, I certainly have to put out a diary post today.

Why is it almost the last minute? Because I have to drive to a friend’s house to watch the Pittsburgh Steelers play the Baltimore Ravens. No, I’m not a football fan – but I most certainly am a Steelers fan. So I won’t be doing any math or blogging for the rest of the day.

(My alter-egos the kid and the grad student have already put in their time on chemical reaction design and abstract algebra respectively.)

As for last weekend… I got distracted by… mathematics. Can you imagine that?

Instead of writing about multicollinearity for the next post, I decided to write about linear dependence. Multicollinearity, after all, is “approximate linear dependence”. So let’s look at “exact linear dependence” first.

My own approach to isolating multicollinearity – figuring out which of the variables are involved – is exactly the approach one would use to isolate linear dependence. It seems to make perfect sense to introduce the subject by looking at linear dependence itself. And the more I look, the more convinced I am of that.

Anyway, that post is somewhere in stage IV: all the mathematics is done, and a fair bit of the discussion has been written. And that was probably all done last Saturday afternoon.

So what happened? Well, I decided to keep looking at multicollinearity itself. To put that another way, I just couldn’t tear myself away from the math. If you will, I was just looking ahead a few posts.

I really, really expect to put out the post about isolating linear dependence this Monday. (It’s already been four consecutive Happenings posts… let’s not make it five.)

As for the blog itself, it passed 90,000 hits last Sunday.