bigjeff5

Karma: 755

bigjeff5 Dec 22, 2013, 5:35 AM
0 points
in reply to: shinoteki’s comment on: Bayes’ Theorem Illustrated (My Way)
In Boy1Tu/Boy2Tuesday, the boy referred to as BTu in the original statement is boy 1, in Boy2Tu/Boy1Tuesday the boy referred to in the original statement is boy2.

That’s why the “born on tuesday” is a red herring, and doesn’t add any information. How could it?

bigjeff5 Dec 22, 2013, 4:55 AM
0 points
in reply to: Jiro’s comment on: Bayes’ Theorem Illustrated (My Way)
I see my mistake, here’s an updated breakdown:

Boy1Tu/Boy2Any

Boy1Tu/Boy2Monday Boy1Tu/Boy2Tuesday Boy1Tu/Boy2Wednesday Boy1Tu/Boy2Thursday Boy1Tu/Boy2Friday Boy1Tu/Boy2Saturday Boy1Tu/Boy2Sunday

Then the Boy1Any/Boy2Tu option:

Boy1Monday/Boy2Tu Boy1Tuesday/Boy2Tu Boy1Wednesday/Boy2Tu Boy1Thursday/Boy2Tu Boy1Friday/Boy2Tu Boy1Saturday/Boy2Tu Boy1Sunday/Boy2Tu

See 7 days for each set? They aren’t interchangeable even though the label “boy” makes it seem like they are.

Do the Bayesian probabilities instead to verify, it comes out to 50% even.

bigjeff5 Dec 22, 2013, 4:48 AM
0 points
in reply to: Jiro’s comment on: Bayes’ Theorem Illustrated (My Way)
Which boy did I count twice?

Edit:

BAny/Boy1Tu in the above quote should be Boy2Any/Boy1Tu.

You could re-label boy1 and boy2 to be cat and dog and it won’t change the probabilities—that would be CatTu/DogAny.

bigjeff5 Dec 22, 2013, 4:16 AM
0 points
in reply to: Jiro’s comment on: Bayes’ Theorem Illustrated (My Way)
No, read it again. It’s confusing as all getout, which is why they make the mistake, but EACH child can be born on ANY day of the week. The boy on Tuesday is a red herring, he doesn’t factor into the probability for what day the second child can be born on at all. The two boys are not the same boys, they are individuals and their probabilities are individual. Re-label them Boy1 and Boy2 to make it clearer:

Here is the breakdown for the Boy1Tu/Boy2Any option:

Boy1Tu/Boy2Monday Boy1Tu/Boy2Tuesday Boy1Tu/Boy2Wednesday Boy1Tu/Boy2Thursday Boy1Tu/Boy2Friday Boy1Tu/Boy2Saturday Boy1Tu/Boy2Sunday

Then the BAny/Boy1Tu option:

Boy2Monday/Boy1Tu Boy2Tuesday/Boy1Tu Boy2Wednesday/Boy1Tu Boy2Thursday/Boy1Tu Boy2Friday/Boy1Tu Boy2Saturday/Boy1Tu Boy2Sunday/Boy1Tu

Seven options for both. For some reason they claim either BTu/Tuesday isn’t an option, or Tuesday/BTu isn’t an option, but I see no reason for this. Each boy is an individual, and each boy has a ¹⁄₇ probability of being born on a given day. In attempting to avoid counting evidence twice you’ve skipped counting a piece of evidence at all! In the original statement, they never said one and ONLY one boy was born on Tuesday, just that one was born on Tuesday. That’s where they screwed up—they’ve denied the second boy the option of being born on Tuesday for no good reason.

A key insight that should have triggered their intuition that their method was wrong was that they state that if you can find a trait rarer than being born on Tuesday, like say being born on the 27th of October, then you’ll approach 50% probability. That is true because the actual probability is 50%.

bigjeff5 Dec 22, 2013, 1:18 AM
2 points
0
in reply to: DanielVarga’s comment on: Bayes’ Theorem Illustrated (My Way)
Just so it’s clear, since it didn’t seem super clear to me from the other comments, the solution to the Tuesday Boy problem given in that article is a really clever way to get the answer wrong.

The problem is the way they use the Tuesday information to confuse themselves. For some reason not stated in the problem anywhere, they assume that both boys cannot be born on Tuesday. I see no justification for this, as there is no natural justification for this, not even if they were born on the exact same day and not just the same day of the week! Twins exist! Using their same bizarre reasoning but adding the extra day they took out I get the correct answer of 50% (14/28), instead of the close but incorrect answer of 48% (13/27).

Using proper Bayesian updating from the prior probabilities of two children (25% boys, 50% one each, 25% girls) given the information that you have one boy, regardless of when he was born, gets you a 50% chance they’re both boys. Since knowing only one of the sexes doesn’t give any extra information regarding the probability of having one child of each sex, all of the probability for both being girls gets shifted to both being boys.

bigjeff5 Oct 11, 2012, 2:32 AM
2 points
in reply to: mfb’s comment on: The Bias You Didn’t Expect
I’m talking about probability estimates. The actual probability of what happened is 1, because it is what happened. However, we don’t know what happened, that’s why we make a probability estimate in the first place!

Forcing yourself to commit to only one of two possibilities in the real world (which is what all of these analogies are supposed to tie back to), when there are a lot of initially low probability possibilities that are initially ignored (and rightly so), seems incredibly foolish.

Also, your analogy doesn’t fit brazil84′s murder example. What evidence does the lottery win give that allows us to adjust our probability estimate for how the gun was fired? I’m not sure where you’re going with that, at all.

The real probability of however the bullet was fired is 100%. All we’ve been talking about are our probability estimates based on the limited evidence we have. They are necessarily incomplete. If new evidence makes both of our hypotheses less likely, then it’s probably smart to check and see if a third hypotheses is now feasible, where it wasn’t before.

bigjeff5 Oct 10, 2012, 9:34 PM
−2 points
in reply to: brazil84’s comment on: The Bias You Didn’t Expect
The probability of both, in that case, plummets, and you should start looking at other explanations. Like, say, that the victim was shot with a rifle at close range, which only leaves a bullet in the body 1% of the time (or whatever).

It might be true that, between two hypotheses one is now more likely to be true than the other, but the probability for both still dropped, and your confidence in your pet hypothesis should still drop right along with its probability of being correct.

So say you have hypothesis X at 60% confidence and hypotheses Y at 40% New evidence comes along that shifts your confidence of X down to 20%, and Y down to 35%. Y didn’t just “win”. Y is now even more likely to be wrong than it was before the new evidence came it. The only substantive difference is that now X is probably wrong too. If you notice, there’s 45% probability there we haven’t accounted for. If this is all bound up in a single hypothesis Z, then Z is the one that is the most likely to be correct.

Contradictory evidence shouldn’t make you more confident in your hypothesis.

bigjeff5 Oct 9, 2012, 4:18 AM
1 point
in reply to: gjm’s comment on: Firewalling the Optimal from the Rational
4-step is what preceded 2-step. I say preceded, but it’s not like 4-step has gone anywhere. It’s still the most common beat pattern for electronic music. It’s just a steady beat in ⁴⁄₄ time with a kick drum on each beat, so it just goes boom boom boom boom with each measure, and it’s super easy to dance to.

Techno and house are pretty much exclusively 4-step.

2-step runs at the same/similar speed as 4-step, and is still in ⁴⁄₄ time, but the drum beat is split up and made more erratic. You’ll often have several drum rhythms going on simultaneously. The effect is that the beat sounds like it is sort of stuttering, sort of like this: boom boom pause boom pause pause boom boom pause boom boom boom (that’s three measure’s worth there). I think Garage was the only real 2-step going on before dubstep, but I’m not real clear on that part of it.

Dubstep gets it beat patterns from 2-step (thus the “step” in the name).

The “Dub” comes from the reggae tradition of sampling pop songs to build a record in an afternoon. That’s why the vast majority of dubstep tracks are remixes—it’s just how you make dubstep. The build ups and drops that are so popular are not necessary for dubstep, and just because a song has that stuff doesn’t make it dubstep. They are just a natural fit for DJ’s (who like to control the energy of a crowd) and a 2-step beat pattern.

It’s not really dubstep if it isn’t heavily sampled with an erratic ⁴⁄₄ beat (aka 2-step).

bigjeff5 Oct 8, 2012, 6:58 PM
2 points
in reply to: brazil84’s comment on: The Bias You Didn’t Expect

What else could it be?

The break distance bias found in the papers?

You can’t use two pieces of contradictory evidence to support the same argument. If the most highly contested cases still have a chance at success, finding 0% success rate at the furthest distance from the last break (because they are the longest cases and therefore placed last) should not increase your belief that there is no bias at work. It should reduce it. How significantly your belief is reduced depends on just how likely you would see 0% success rates at a high distance from break due only to scheduling, but I can’t see any way it could legitimately raise your belief that there is no bias.
What links here?
- TheOtherDave's comment on The Bias You Didn’t Expect by Psychohistorian (Oct 9, 2012, 3:09 PM; 2 points)

bigjeff5 Oct 8, 2012, 4:35 PM
0 points
in reply to: brazil84’s comment on: The Bias You Didn’t Expect
I agree that any contested case should be longer than an uncontested, however are there not cases where the prosecution simply doesn’t need to go through a lengthy argument to prove their case? Prosecution lays out X, Y, and Z evidence that is definitive, and therefore the prosecution doesn’t need to spend a lot of time arguing. Are these types of cases not generally shorter than cases that are contested but more likely to succeed? Or does a lengthy defense attempting to weasel out of the evidence make up for a short prosecution? And are these specific cases few and far between?

I doubt it, but there chances of success are surely worse than uncontested applications.

In this context I could believe a very low success rate, but the researchers found a 0% success rate for a number of courts. That still makes me suspicious. I’m still not sure what “very low success rate” means for parole hearings though. Is 20% low? Is it more like 5%? Somewhere in between? Obviously, the lower a reasonable success rate for these types of cases the more likely you’ll see 0% rates in different courts, just based on chance.

I don’t know enough about the details of Israeli parole hearings to speak definitively about that. I can say >as a lawyer that many times I have made uncontested applications which were denied. This was not in a >criminal or parole context.

Fair point. Like I said above I’m not really sure what my expectations should be for a reasonable success rate in these types of cases (or cases in general). Question though, did these applications tend to be closer to or further from a break than your more successful uncontested applications? (obviously purely anecdotal, but I’m sure you see my point)

bigjeff5 Oct 8, 2012, 3:15 PM
0 points
in reply to: brazil84’s comment on: The Bias You Didn’t Expect
I can certainly buy that, but would there really be zero people who apply even though they don’t have much chance of winning? I know a few stubborn people who I would expect to apply anyway even if they didn’t have much chance of success. I’d be surprised to find out that the prison system has an insignificant number of people who are like that as well.

Also, do the most highly contested applications (and therefore the longest, and therefore placed last on the docket) really have 0% chance of success? If so, would not those applications be better off not applying at all? It seems to contradict the idea that an application with 0% chance of success would not be filed.

Lastly, with only a 65% approval rate for the early applications, I’m pretty surprised that the prosecution doesn’t care about them very much. If they were completely uncontested wouldn’t you expect closer to a 100% success rate?

bigjeff5 Oct 7, 2012, 11:55 PM
2 points
in reply to: brazil84’s comment on: The Bias You Didn’t Expect
I don’t see any reason there wouldn’t be the inverse as well. That is, applications which are immediately rejected, and therefore quite short.

I also find it suspicious that the most highly contested applications would also be the least likely to be approved. Presumably these are the ones which are borderline, and require much argument, pro and con, to come to a decision. Immediate rejections wouldn’t require long arguments, and neither would immediate acceptances. Under the above hypothesis, both of these types of cases should be early in the session.

If there were no bias and the cases were arranged by length, I would expect to see nearly 50% of the lengthy contested cases, to be accepted. Or, if that many are simply not accepted, some number significantly greater than 0%. For a slightly different arrangement, if the immediate rejections were placed last in the session I would expect the acceptance rates to start at nearly 100% and progress down to 0%. Unless, of course, there is no such thing as a quick, immediate acceptance parole case, in which case the argument doesn’t work anyway. If they are all long there isn’t much point in arranging by likelihood to be accepted.

bigjeff5 Sep 13, 2012, 9:09 PM
2 points
in reply to: Emile’s comment on: How to deal with someone in a LessWrong meeting being creepy
Body language coaching doesn’t just exist, it’s an industry. It is typically associated with public speaking, salesmanship, etc, and there are a lot of places (and books, and online resources, etc) to get training. In fact, one of the linked blogs in the OP, “Paging Dr. NerdLove”, is completely dedicated to helping men who are bad at inter-personal communication with women (i.e. socially awkward) get better at it, which includes quite a lot of body language training.

It’s reasonably well known that body language comprises a significant portion of interpersonal communications, so just like you’d expect with other languages there are quite a lot of resources for learning the language, if you take some time to look for them.

And of course, like any language, the resources are of varying quality and usefulness. But the general idea of “you get what you pay for” holds.

bigjeff5 Sep 13, 2012, 4:13 PM
10 points
in reply to: MixedNuts’s comment on: How to deal with someone in a LessWrong meeting being creepy
The heart of the problem is body language.

It’s an actual language that must be learned and spoken, but a lot of people for some reason never learned it, or learned it poorly.

When these people interact with strangers, it’s exactly like the guy with a bad understanding of a foreign language who tries to speak it, and instead of saying “Hi, are you friendly? Lets be friends!” he says “Hi, I want swallow your head!”

I hope you can see why people wouldn’t like someone who goes around talking like that on a regular basis, and that the problem really does lie with the speaker, not the people he’s speaking to.

What’s worse, if he doesn’t understand what others are trying to tell him (in the language he speaks poorly—aka body language) when he makes these kinds of statements he certainly can remain oblivious to the problem and be unable to fix it himself. If a person in that situation never meets a kind soul willing to help him speak correctly then he really is screwed, and there isn’t much he can do about it unless he recognizes the problem on his own and seeks help.

bigjeff5 Sep 3, 2012, 12:23 AM
1 point
in reply to: DanielLC’s comment on: The Parable of the Dagger
I’m still not getting the difference. He chose the second box because he deduced the the key must be there based on the assumption that one of the inscriptions was true. There is no equivalence between assuming a key in the second box and deducing a key in the second box based on a false premise.

However, assuming one of the inscriptions is true and assuming a correlation between the inscriptions and the contents of the box seem the same to me. He can’t deduce a correlation between them, because the only basis for such a correlation is the existence of the inscriptions and the basic format of the king’s challenge (which was not identical to the jester’s own riddle). There is nothing in the first inscription to suggest a correlation exists, particularly if he determined that the inscription must be false! It has to be a faulty assumption, and I don’t see how it is different than assuming one of the inscriptions must be true, other than semantically.

I’m not trying to be obtuse here, I’m just not seeing the difference between what you’ve said and what I’ve said.

bigjeff5 Sep 2, 2012, 6:25 PM
4 points
0
in reply to: DanielLC’s comment on: The Parable of the Dagger
For the inscriptions to be either true or false, they would have to correlate with the contents of the boxes. If he didn’t assume this correlation existed, why would he have bothered trying to solve the implied riddle, and then believe upon solving it that he could choose the correct box?

The assumption that one of the inscriptions is true is also the assumption that the contents of the boxes correlate with the truthfulness of the inscriptions. And the key point is that neither inscription need be true, because the contents of the boxes don’t correlate with the truthfulness of the inscriptions. And in fact, neither inscription was true.

In other words, I don’t understand why you’re arguing a simple clarification of essentially the same point you made.

bigjeff5 Sep 2, 2012, 6:14 PM
2 points
in reply to: [deleted]’s comment on: 37 Ways That Words Can Be Wrong
I think that’s basically the point—the argument is technically valid, but it is wrong, and you got there by using “human” wrong in the first place.

Socrates is clearly human, and the definition on hand is “bipedal, featherless, and mortal”. If Socrates is mortal, then he is susceptible to hemlock. When Socrates takes hemlock and survives, you can’t change the definition of “human” to “bipedal, featherless, not mortal”. You’re still using the word “human” wrong.

What’s telling here is that you don’t say “Socrates is not human” because you already know he is. If you do go down that route, even though your arguments are correct the conclusion will be intuitively wrong—just another valid but incorrect argument. There are undefined characteristics regarding what it is to be human which carry significantly more weight than the definition itself, and instead of encapsulating them in the definition you’ve tried to ignore them—tried to make reality fit your definition rather than the other way around.

bigjeff5 Sep 1, 2012, 11:42 PM
25 points
0
in reply to: DanielLC’s comment on: The Parable of the Dagger
Unlike the jester’s riddle, the king never claimed there was any correlation between the contents of the boxes and the inscriptions on those boxes. The jester merely assumed that there was.

bigjeff5 Sep 1, 2012, 6:29 PM
1 point
in reply to: johnlawrenceaspden’s comment on: Two More Things to Unlearn from School
It couldn’t be that, I was raised among the proletariat. Not much prestige dialect signalling there. (There is some, of course, but nothing like the bourgeoisie.)

bigjeff5 Sep 1, 2012, 6:17 PM
8 points
in reply to: johnlawrenceaspden’s comment on: Two More Things to Unlearn from School
I think in my previous post the implication is that I believe the punishment was unwarranted. That is not the case (though I certainly felt that way at the time). I simply felt the reason given for the detention was less important than the experience of realizing that authority figures can be wrong.

It was entirely appropriate for the teacher to give me detention, because I actually was interrupting class when she was trying to teach, and I don’t think I was being particularly helpful to the rest of the students. What she was teaching was correct, as far as I can remember, however there isn’t much a person can do about 40+ years of poor habits when it comes to speaking English.

She was in a bad position, and did a reasonable job under the circumstances. I was just a bratty little smart aleck making her life difficult.