The many questions-not-worth-their-own-thread question thread XV

[Japanrocks12]

Yeah, true randomness, much like the true location of an electron at any given point in time, can't be measured.

 

[Atticus]

Well, randomness isn't obvious concept, and I've understood there's pretty hardcore maths done about it, for example for the question whether decimals of pi can be considered random or not.

I know nothing about that, but you could think it this way for example: A deck is in random order, if there's a 1/52 chance for any card to occupy any place in it. So there's 1/52 chance that the top card is queen of hearts for example, and there's 1/52 chance for the bottom card to be seven of spades.

If you take a deck, and examine it's cards, you can not of course attribute those probabilities. When you have looked at the top card, and it is ace of clubs, the probability for that top card is 1.

However, you can calculate, before you examine the deck, what are the chances that consecutive cards follow each others in the deck. Suppose for this an order to the colors, say hearts, diamonds, clubs and spades. Now the chances for two first cards to be consecutive (and in the right order) is 51/52 * 1/51=1/52. Any card, but the king of spades will do for the first card (KoS doesn't have a successor), and for the rest of the 51 cards there are exactly one card that can be on the second spot.

You can calculate the probability that there are k cases of cards in right order in a random deck. Or you can in principle, it might take some effort, and I'm not going to do it. Some k:s have very low probability. For k=51 it is 1/52! and I'd guess it's under 1/100 even for k=12. Note that also k=0 has probably very low probability.

Now you could define this as a measure for randomness of the deck: The bigger the probability for deck's "straights", the more random deck. This of course has nothing to do with how the cards came to that order. You can shuffle the deck properly, and the cards may turn out to be in just correct order, but anyhow the deck wouldn't be random. Or you can place the cards so that the probability of straights is maximized, and the deck is random.

Now there's some problems with this. First of all, consider a deck that is in full reverse order: King of spades, Queen of spades, Jack of spades,... . With our definition for the randomness, the k would be 0, and it's probability much more than for the full order. Why would this deck be anymore random however?

And then, you can consider different orders. Let's say you paint the Roman numerals I,II,III,...,L,LI,LII to the cards in random (!) order. Then you shuffle them, and the cards are very random in the previous definition, but the roman numerals turn out to be in the reverse order LII,LI,L,...,II,I. Or less dramatic example, they may make 13 four card straights of Roman numerals. Why would this deck be more random than a fresh deck?

But anyhow, as I said, I'm not learned on these matters, just speculating. You might get better answer in Let's discuss mathematics-thread.

Dachs, I'd still like to hear, what do you think about the meanings of the word "science". I understood that you didn't say that the word doesn't have the meaning that I suppose it has, but instead that history doesn't meet the criteria of the dictionary I quoted.

that's what i thought, but then, i considered this, if it is 9am in one zone and 9pm in another zone, does that make the settings on the clock right twice at the same time?


also, there r a bunch of wierd time zones around the world....for example, venezuela and iran seem to be on 1/2 hour offsets

Ok, but we have to simplify a little bit to keep it gentleman-worthy.

If the clock is right twice at the same time, it still counts only as one, I think, since you were asking how many times it is right.

what is the difference between an interest and an obsession?

Yours is an obsession.

EDIT: Half hour x-post

 

[Dachs]

Dachs, I'd still like to hear, what do you think about the meanings of the word "science". I understood that you didn't say that the word doesn't have the meaning that I suppose it has, but instead that history doesn't meet the criteria of the dictionary I quoted.

Theoretically, the definition exists; rather like how the word "nice" can technically "simple, foolish, ignorant", but doesn't.

 

[ParadigmShifter]

Well, randomness isn't obvious concept, and I've understood there's pretty hardcore maths done about it, for example for the question whether decimals of pi can be considered random or not.

I know nothing about that, but you could think it this way for example: A deck is in random order, if there's a 1/52 chance for any card to occupy any place in it. So there's 1/52 chance that the top card is queen of hearts for example, and there's 1/52 chance for the bottom card to be seven of spades.

If you take a deck, and examine it's cards, you can not of course attribute those probabilities. When you have looked at the top card, and it is ace of clubs, the probability for that top card is 1.

However, you can calculate, before you examine the deck, what are the chances that consecutive cards follow each others in the deck. Suppose for this an order to the colors, say hearts, diamonds, clubs and spades. Now the chances for two first cards to be consecutive (and in the right order) is 51/52 * 1/51=1/52. Any card, but the king of spades will do for the first card (KoS doesn't have a successor), and for the rest of the 51 cards there are exactly one card that can be on the second spot.

You can calculate the probability that there are k cases of cards in right order in a random deck. Or you can in principle, it might take some effort, and I'm not going to do it. Some k:s have very low probability. For k=51 it is 1/52! and I'd guess it's under 1/100 even for k=12. Note that also k=0 has probably very low probability.

Now you could define this as a measure for randomness of the deck: The bigger the probability for deck's "straights", the more random deck. This of course has nothing to do with how the cards came to that order. You can shuffle the deck properly, and the cards may turn out to be in just correct order, but anyhow the deck wouldn't be random. Or you can place the cards so that the probability of straights is maximized, and the deck is random.

Now there's some problems with this. First of all, consider a deck that is in full reverse order: King of spades, Queen of spades, Jack of spades,... . With our definition for the randomness, the k would be 0, and it's probability much more than for the full order. Why would this deck be anymore random however?

And then, you can consider different orders. Let's say you paint the Roman numerals I,II,III,...,L,LI,LII to the cards in random (!) order. Then you shuffle them, and the cards are very random in the previous definition, but the roman numerals turn out to be in the reverse order LII,LI,L,...,II,I. Or less dramatic example, they may make 13 four card straights of Roman numerals. Why would this deck be more random than a fresh deck?

But anyhow, as I said, I'm not learned on these matters, just speculating. You might get better answer in Let's discuss mathematics-thread.

Dachs, I'd still like to hear, what do you think about the meanings of the word "science". I understood that you didn't say that the word doesn't have the meaning that I suppose it has, but instead that history doesn't meet the criteria of the dictionary I quoted.



Ok, but we have to simplify a little bit to keep it gentleman-worthy.

If the clock is right twice at the same time, it still counts only as one, I think, since you were asking how many times it is right.



Yours is an obsession.

EDIT: Half hour x-post

There are no "streaks" of consecutive cards in a reverse order deck, which you would expect to come up some statistically significant number of times.

Very little is known about irrational or (stronger criterion) transcendental numbers like sqrt(2), pi and e, except for certain numbers which are constructed so as to have certain properties.

For example, we say a base-n decimal expansion is "normal" if each of the digits 0...n-1 occur with equal probability in the expansion base-n. It is not known whether the expansion of pi is normal in any base. EDIT: "Almost all" real numbers are normal however

pi does however pass most tests for randomness we have thought of.

 

[madviking]

What are some good sources for Physics 101 level E+M?

Tipler sucks biblical donkey and I need something that will allow me to actually understand the material, rather than gloss over it with smoke and mirrors.

I've been referred to University Physics (Ford, Freedman, and Young) and Griffiths, but both are really expensive as of now...

 

[PlutonianEmpire]

If one were to become co-authors with someone to write a book, would they need a legally binding contract or some other legal document? If so, what exactly would they need?

 

[Brian Shanahan]

They probably would, but I'm not sure what kind.

 

[Cutlass]

Any business partnership should have a contract. But unless it's a big money deal, you probably don't need a lawyer to write one up. Just type up an agreement, print several copies, have both parties sign, and have the copies notarized. Then if he tries to screw you out of your share you have a document that proves the agreement for the courts.

 

[ZeletDude]

So I've seen many spoilers say "Spoiler for X" in the small black/grey font right above the Spoiler, how do you do this? I've always wondered

 

[Cutlass]

So I've seen many spoilers say "Spoiler for X" in the small black/grey font right above the Spoiler, how do you do this? I've always wondered

Quote this and look at the code.

 

[_random_]

So I've seen many spoilers say "Spoiler for X" in the small black/grey font right above the Spoiler, how do you do this? I've always wondered

Spoiler This is how you do it. :

Add an equality sign in the first tag followed by the text you want within the bracket. Quote this post for an example.

 

[ZeletDude]

Spoiler This is how you do it. :

Add an equality sign in the first tag followed by the text you want within the bracket. Quote this post for an example.

Thanks!

 

[Dachs]

[spoiler=you do it like this]:D[/spoiler] gives

Spoiler you do it like this :

 

[Gamemaster77]

You guys sound like your on the "lets talk mathematics" thread

 

[Atticus]

There are no "streaks" of consecutive cards in a reverse order deck, which you would expect to come up some statistically significant number of times.

Yeah, but I'd be ready to say without any calculations that no streaks is much much much more probable than full order, yet a deck in full reverse order is by intuition just as unrandom as the one in full order.

Funny thing about playing cards: some people complain that the cards haven't been shuffled, and fail to notice that they have been dealt every third or fourth card, or in what order the cards were dealt.

 

[ParadigmShifter]

Well that's just one test. You'd also expect runs of red and black cards (or suits) fitting a certain distribution as well for a shuffled deck.

EDIT: We are talking about a hypergeometric/multivariate hypergeometric distribution for a deck of cards: http://en.wikipedia.org/wiki/Hypergeometric_distribution

Maybe this does belong in the maths thread

 

[_random_]

How do I copy image URLs in Facebook's new photo viewer?

 

[madviking]

prntscrn
imgur

 

[cardgame]

How do I copy image URLs in Facebook's new photo viewer?

If you have chrome, you can right click on the image, hit reload, then right click on the new image that comes up and click open image in new tab. then you can copypasta the url

 

[_random_]

Ctrl+click works as well as it turns out. It's a great assistance in trolling Omegle.