IlyaShpitser comments on How urgent is it to intuitively understand Bayesianism? - Less Wrong

7 Post author: adamzerner 07 April 2015 12:43AM

You are viewing a comment permalink. View the original post to see all comments and the full post content.

Comments (24)

You are viewing a single comment's thread. Show more comments above.

Comment author: dhoe 08 April 2015 09:27:14AM 4 points [-]

What are the practical benefits of having an intuitive understanding of Bayes' Theorem? If it helps, please name an example of how it impacted your day today

I work in tech support (pretty advanced, i.e. I'm routinely dragged into conference calls on 5 minutes notice with 10 people in panic mode because some database cluster is down). Here's a standard situation: "All queries are slow. There are some errors in the log saying something about packets dropped.". So, do I go and investigate all network cards on these 50 machines to see if the firmware is up to date, or do I look for something else? I see people picking the first option all the time. There are error messages, so we have evidence, and that must be it, right? But I have prior knowledge: it's almost never the damn network, so I just ignore that outright, and only come back to it if more plausible causes can be excluded.

Bayes gives me a formal assurance that I'm right to reason this way. I don't really need it quantitatively - just repeating "Base rate fallacy, base rate fallacy" to myself gets me in the right direction - but it's nice to know that there's an exact justification for what I'm doing. Another way would be to learn tons of little heuristics ("No. It's not a compiler bug.", "No. There's not a mistake in this statewide math exam you're taking"), but it's great to look at the underlying principle.

Comment author: IlyaShpitser 09 April 2015 08:03:03AM *  2 points [-]

Troubleshooting is a great example where a little probability goes a long way, thanks.


Amusingly, there was in fact an error in the GRE Subject test I once took, long ago (in computer science). All of the 5 multiple choice answers were incorrect. I agree that conditional on disagreement between test and testtaker, the test is usually right.

Comment author: othercriteria 10 April 2015 01:42:16PM 1 point [-]

The Rasch model does not hate truth, nor does it love truth, but the truth if made out of items which it can use for something else.