Mike was a nice guy. In the way that left-handed math geniuses are nice guys. He’s smart and he knows he’s smart. He really wants to help. Let me restate that. He really wants to get paid to do his job. When I called his employer (a nanny and tutor renting operation) they weren’t sure they had anyone who could really do tutoring for a graduate school student. Mike volunteered.
You should sympathize with Mike. He teaches Chemistry and Calculus. He’d just have to brush up a little, right? Right. He had no idea what he was in for. To be fair, neither did I. The questions I have about Statistics are very basic. Without going too far into it, I’ll try to explain.
We were dealing with bell curves when I arrived. Bell curves and hypothesis testing. Zscores, Tscores, and rejection regions. One of the questions I had was what’s under the line of the curve. Is that all people? is it answers? Is it confidence? When I’m doing means testing and I come up with an answer, (1.684 for example) where is that answer on the curve? Is it on the line? or in the hump of the curve.
Mike would get confused about my questions. Sometimes when he got confused he’d smile and shake his head. Sometimes he’d pinch the bridge of his nose. Sometimes he’d say, “What do you mean?” Seemed pretty basic to me. Sometimes he’d answer and his answer would be wrong. Mike didn’t admit being wrong. Even when he made me miss two questions on my midterm with his wrong-ass answers.
He got confused when I asked what a certain kind of equation or theory told us about the real world. There’s this thing you can do with graphs and taking the means of a group of means.Sampling distribution of the sample means, it’s called, I think. You can do a little example of it if you want here. If you do it enough, even a very bizarrely irregular dataset will become regularized. I wanted to know why it was useful to take something so unusual and make it look regular. You could have a really unusual distribution, little peaks and valleys or two big peaks, whatever. If you run it through this process of equations, it would become a normal curve which you could then use to learn stuff.
How does that not use manipulation of data to tell a lie? Well, if I was describing it right, it sounded like my stats professor was maybe wrong. He couldn’t say he didn’t know. Especially when he didn’t know. He spent about 25% of my/his time/money flipping through my stats book. Shit, I can look up stuff in the book for free myself.
I gave him an example (one that jumped to mind) of a therapeutic intervention that you wanted to test. Say you have a therapy that you think will reduce the number of some hand-flapping tic in the kids in your special ed classroom. You want to test your therapy against a control group. In the control group you do nothing and measure the number of hand flaps one day and the next day. In your experimental group, let’s say you cut off all the hands of the children. You count the hand flaps one day, cut the hands off and then count the hand flaps the day after that. Your results should be pretty drastic. It won’t look like any kind of a curve. It will be a kind of block showing all the kids with total absence of flapping behavior. If you run that block shaped graph through this special process enough times, the block (in theory), will become normalized to look like a bell curve. Then you can analyze the curve in all sorts of useful ways.
For whatever reason, Mike got stuck on the amputation of the hands on the kids in my experimental group and he was at a loss to explain to me the theoretical explanation. I really needed someone who knew enough about the subject that they wouldn’t get distracted by my weird examples. Mike wasn’t the guy. “Can we make it something else? like we tied their hands down?” Sure we could, but I still wanted to know how the new curve could really be useful to analyze anything in the real world. Isn’t that what statistics is supposed to do?
His fate was sealed when I changed the answer to a question because of what he told me, and got it back marked incorrect. The right answer was the one I had first. I didn’t go back, but I think I passed the class anyway.