rvern

No, this is one of the greatest arguments for small government or no government. People are more rational when the cost to them of being irrational is larger. Voting for good policies is a public good. When a voter is one among three hundred millions of citizens, only 1/300,000,000 (on average) of the benefits of the vote befall the individual voter. This gigantic externality means that the democratic market will severely underproduce votes for good policies. Simultaneously, social desirability bias means that voters have a strong incentive to believe in policies that are harmful to them but that make them look good to other people. Since the cost to them of being wrong about politics is so small and the benefit large, voters have gravely irrational beliefs. This conclusion is consistent with the results from social science that show that voters are ignorant about politics and with the widespread agreement with protectionist tariffs, price controls, restrictions on immigration, and many other policies that cause great economic harm.

“Suppose you’re on a game show, and you’re given the choice of three doors: Behind one door is a car; behind the others, goats. You pick a door, say No. 1, and the host, who knows what’s behind the doors, opens another door, say No. 3, which has a goat. He then says to you, ‘Do you want to pick door No. 2?’ Is it to your advantage to switch your choice?”

Let A be the event that the car is behind door 1, B that the car is behind door 2, and C that the car is behind door 3. Let E be the event that the host opens door 3. We assume that the car is initially equally likely to be behind each door and that the host opens a door with a goat at random, never opening the door we picked.

Since A, B, and C are exhaustive and mutually exhaustive propositions, we can calculate the marginal probability of E by using the law of total probability:

P(E) = P(E ∧ A) + P(E ∧ B) + P(E ∧ C).

Bayesians like to define joint probability from conditional probability instead of the reverse; that is, define P(A ∧ B) as P(A | B) P(B) instead of P(A | B) as P(A ∧ B) / P(B).

So P(E ∧ A) = P(E | A) P(A). P(E | A) is 1/2 because we picked door 1, the car is behind door 1, and the host chooses at random a door that has a goat, of which there are two: 2 and 3. P(A) is 1/3. Therefore P(E ∧ A) is 1/2 × 1/3 = 1/6.

Similarly, P(E ∧ B) = P(E | B) P(B). P(E | B) is 1 because we picked door 1 so the host will not open door 1 and we assume the car is behind door 2 so the host will not open door 2, leaving only door 3 to be opened. P(B) is 1/3. Therefore P(E ∧ B) is 1 × 1/3 = 1/3.

P(E ∧ C) = P(E | C) P(C). P(E | C) is 0 because the host will never open the door the car is behind. P(C) is 1/3. Therefore P(E ∧ C) is 0 × 1/3 = 0.

So P(E) = 1/6 + 1/3 + 0 = 1/2. We know that the host opened door 3 (this is E), so the car cannot be behind door 3. How likely is it to be behind door 1? By Bayes’ theorem,

P(A | E) = P(E | A) P(A) / P(E).

We said earlier that P(E | A) is 1/2, P(A) is 1/3, and P(E) is 1/2. So P(A | E) = (1/2 × 1/3) / (1/2) = 1/3.

Given E, the car must be behind door 1 or door 2 since the host opened door 3. Therefore the sum of P(A | E) and P(B | E) must be 1. P(A | E) is 1/3, so P(B | E) is 2/3. The car is more likely to be behind door 2 than door 1. We initially picked door 1, so, if we want the car, we should switch.

Bayes’ theorem says no such thing. Your friend is wrong, but please do not let this reflect badly on the Bayesian interpretation of probability in general—it has nothing to do with this.

Live a modern life, comfortable by modern standards? You’re right about that. But people in the past lived in worse conditions that were considered modern and comfortable then and credit ratings, by making the market for loans more efficient than it was before (however bad it may still be, it’s better than what it replaced), contributed to the improvements. You want to have your cake and eat it too, and it would be nice if that was possible but it is not because nobody is going to give you cheap loans if it comes with too much risk.

The institutions give you cheap loans in exchange. This has opportunity costs. Giving you cheap loans is not free for these institutions. They could be investing their money elsewhere instead. They would do so if it wasn’t for the fact that having this information about you reduces the risk just enough that they prefer giving you the cheap loans to investing their money elsewhere. People who are offered these terms are offered a fair deal that is a win for both parties and that they are offered a fair deal is exactly the reason they accept it.

There is no externality here because the costs fall entirely on the person who takes the decision. People, myself and quite possibly yourself included, really do want to sign up with 30 marketing companies to save 5% on a car.

Equifax has an incentive not to get things wrong because their customers care about having accurate information. Nationalizing credit ratings would remove this incentive. That Equifax still gets things wrong does not imply that things would not be even more wrong if it was nationalized.

There are public instances running GitLab CE at framagit.org and 0xacab.org.

> I'd believe Wikipedia less than either.

That's where you make a mistake. Whatever the reason, the Wikipedia articles on the g factor, the intelligence quotient and Cattell–Horn–Carroll theory represent better what is widely accepted in the field than any other source. This somehow also turns out to be true for other academic fields.

Anyway, when source A says explicitly that source B is wrong but source B makes no such claim about source A, you should usually believe source A. But in this case you can know that the study is right by just learning for yourself what does happen to be widely accepted in the field and why it is widely accepted.

I cannot find much valuable content on deletionpedia.org in general and nothing interesting about clocks. If you know about articles with valuable information that were lost, you can ask an administrator to give you the page's text. Full edit history for all deleted pages is kept and more than a hundred administrators are happy to give it to you, it's just not publicly viewable because it can contain copyright violations, personal information, and so on.