## A quiz of marginal interest

Two things we know.

(1) Scientific terminology is burdened with the baggage of history, which now makes no logical sense. So… early type galaxies are the ones with late type stars? Errr… And which of these terms relates to a sequence in time? Neither. Right. Very helpful.

(2) When you have to teach something, you finally figure out things that have been bugging you for years.

(3) Nobody expects the … oh. Anyway. Often (1) and (2) combine to make a particularly thick fog.

For some time the term “marginalisation” had been nagging at me, but I ignored it because I had other stuff to get on with. I am referring to the term in statistics. You have a probability density function of two variables, f(x,y), but decide that y is “interesting” and x is “uninteresting”. You then integrate over x to get a PDF p(y) for y alone. This known as “marginalising over x”.

So here is the quiz. My guess is only about seven people will want to take it, but I can’t resist it.

Rule (a) Andrew Liddle is not allowed because I already told him the answer in the pub. Rule (b) No Googling. Rule (c) Never talk about  Stats Club.

### 10 Responses to A quiz of marginal interest

1. “(3) Nobody expects the … oh. Anyway.”

I really wasn’t expecting this. However, just a few seconds before checking the RSS feed for your blog, I noticed an item on a German news site saying that Monty Python are planning a comeback.

2. andyxl says:

Well .. thirteen votes already which is twice as many as I was expecting for something so geeky… Meanwhile.. may not have been obvious, but if you vote “other” the idea of the blank box is you type in your other explanation. This is slightly more interesting than just “none of the above”

3. andyxl says:

Ahh … the reasons put in “other” don’t appear to become public. For your amusement, our one “other” vote so far said “I would write the reason here but I don’t have room in the margin”. Must be Fisher’s last theorem.

4. andyxl says:

Thats twenty two votes – genuinely much more than I expected! (Out of a couple of hundred viewers…) Any more? I will leave it open for tomorrow, and then maybe reveal the answer in a separate post

5. Mark says:

Perhaps it’s my setup (though I don’t know where, and Firefox removed control of javascript this past summer), but Firefox (run both on Linux and a Mac) doesn’t show the poll. Safari did fine (Mac) as did Chrome (Linux).

• andyxl says:

err.. thats curious. I am using Firefox myself (on a Mac) and it looks fine. Also.. don’t understand what you mean by “removed control of javascript”. Presumably your browser runs javascript ok – they all do don’t they??

• John says:

There used to be an option in the Firefox preferences to disable Javascript, but that was removed. I think Mark’s point is that he can’t have broken things by accidentally turning off Javascript, since the option no longer exists.

Actually, though, it is possible to disable Javascript in Firefox by going to the URL about:config and setting javascript.enabled to false. I imagine that’s unlikely to be something you do by mistake, though.

• Mark says:

Hi sorry, was away and didn’t get back to this. Yes, John has it correct about the intention of my statement. I just checked, and javascript.enabled is set to true in FF (version 25.0.1 on Mac running OS10.7.5), so I don’t know what is going on with it…

6. andyxl says:

Thirty nine votes so far, and its neck and neck between “marginal interest” and “marginal profits”…..

7. […] dokey. Better reveal the solution to the stat-geek marginalisation quiz. There were sixty two […]

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