Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

What does randomness look like?

empiricalzeal.com

Post reply on HN
Print view View original

71–80 of 123 posts

Re: What does randomness look like?

#71

Post by dspeyer »

baddox wrote: post #48
henrikschroder wrote: post #23

Earlier quoted context omitted.

Oh yes. Our intuition is that random is fair and uniform, but it's absolutely not. I was bit by another random quirk in World of Warcraft. There was a long-running achievement called "What a Strange Long Journey it has Been", which took at least a year in real-time to complete, and you had to actively play during each of the ten or so in-game festivals and holidays, and do some quests and tasks during each. If you mi…

> Oh yes. Our intuition is that random is fair and uniform, but it's absolutely not. But a uniform distribution is random, isn't it? This sort of phrasing is rampant in this thread, and I'm confused by it. How can a uniform distribution be considered non-random, or "less" random than another distribution?

A distribution is the probability of various values before the random selection takes place. Uniformity is what we do or don't see afterward.

The results of a uniform distribution, applied randomly a large number of times are less uniform than intuition predicts.

Re: What does randomness look like?

#72

Post by [deleted] »

Zakharov wrote: post #67
fmx wrote: post #66

Earlier quoted context omitted.

You couldn't possibly miss all 8 pieces. As soon as you make one attempt you'll get one piece.

Henrik's math calculated the chance of missing the "I love you" piece each time. The chance of missing any one other piece each time is the same.

[deleted]

Re: What does randomness look like?

#73

Post by Dylan16807 »

baddox wrote: post #44
thurn wrote: post #14

Earlier quoted context omitted.

This is actually an important lesson for game designers. Real randomness is very frustrating for players! Games should be designed to not be random. For example, there's an expansion to The Settlers of Catan that lets you use cards instead of dice to ensure a nice smooth distribution of resources... I think it's a lot more fun!

I was under the impression that a uniform distribution is still considered random, but that there are simply many other random distributions. If you have a flat 1/10 chance of receiving a certain item, then sure, you might do the task 30 times without getting it. But if it were programmed such that you will always receive the item at some point within the first 10 completions of the task (i.e. 10% of players receive…

I can give you one simple argument. Ten items shuffled have 10! entropy, while ten independent rolls have 10^10 entropy. How is that not far less random?

Re: What does randomness look like?

#74

Post by _casperc »

henrikschroder wrote: post #11

Back in the day I was in a raiding guild in World of Warcraft. And back then, each boss monster in a raid dungeon had a loot table, and when you killed it, your raid got a few pieces of random loot. And I don't know how many times I, and the other guy in the guild who understood statistics, had to explain to the others that random doesn't mean uniform. If a certain piece of armour has a 1/X chance to drop from a boss…

I have another anecdote from WoW regarding randomness.

The raid boss Onyxia (a great big dragon in a cave, which you could only kill once a week as i recall) had a phase where she would take off and fly above the raid. Once in a while she would then do a deep breath, a fire attack which had a high chance at killing you if it hit you.

Now, all sorts of tactics emerged on how to handle the fire attacks. One that stuck for a very long time was that the number of DOTs (Damage Over Time) would lower the number of deep breaths you got.

I'm sure there were other theories as well, but this one stuck for years with raid leaders yelling at warlocks, the class with most dots, to add more dots and even stacking the raid with warlocks to get as many dots as possible (we need at least 4 warlocks to take her).

In the end there was a developer (or just Blizzard employee) who admitted that it was in fact random. This story pops back in my head once in a while because I think we do this a lot on larger scales too without realizing it: See some phenomenon caused by randomness, come up with a theory, and because it is not easily refuted (after all it works most of the time right?) it becomes common knowledge that everyone follows.

Re: What does randomness look like?

#75

Post by Dylan16807 »

Zenst wrote: post #29

True randomness is a system that say generates a 10 digit number and 11111111 has the same odd's as appearing as the other permutations. But then thats not strictly true as we all know any system that monitors the outcome (a good example will be fruit machines) to make sure there is a even distribution of all permutation will in essence remove that level of definition we like to think as truely random. With that it g…

There is actually no such thing as a random or not random number. There are only random and not random generators. Whether a fruit machine is random depends on how is defines/ensures evenness.

Re: What does randomness look like?

#76

Post by baddox »

Dylan16807 wrote: post #73
baddox wrote: post #44

Earlier quoted context omitted.

I was under the impression that a uniform distribution is still considered random, but that there are simply many other random distributions. If you have a flat 1/10 chance of receiving a certain item, then sure, you might do the task 30 times without getting it. But if it were programmed such that you will always receive the item at some point within the first 10 completions of the task (i.e. 10% of players receive…

I can give you one simple argument. Ten items shuffled have 10! entropy, while ten independent rolls have 10^10 entropy. How is that not far less random?

Because amount of entropy has nothing to do with "amount of randomness."

Re: What does randomness look like?

#77

Post by endtime »

6ren wrote: post #20
henrikschroder wrote: post #11

Back in the day I was in a raiding guild in World of Warcraft. And back then, each boss monster in a raid dungeon had a loot table, and when you killed it, your raid got a few pieces of random loot. And I don't know how many times I, and the other guy in the guild who understood statistics, had to explain to the others that random doesn't mean uniform. If a certain piece of armour has a 1/X chance to drop from a boss…

A market would also fix this, in effect averaging over the entire population. Given players' anger at pieces not dropping as often as they "should", the market would converge approximate the true ratio between drop frequencies of different pieces.

Except that the most desirable loot was invariably soulbound: http://www.wowwiki.com/Soulbound

Re: What does randomness look like?

#79

Post by Dylan16807 »

baddox wrote: post #76
Dylan16807 wrote: post #73

Earlier quoted context omitted.

I can give you one simple argument. Ten items shuffled have 10! entropy, while ten independent rolls have 10^10 entropy. How is that not far less random?

Because amount of entropy has nothing to do with "amount of randomness."

> entropy is a measure of the uncertainty in a random variable

Re: What does randomness look like?

#80

Post by endtime »

lutusp wrote: post #49
baddox wrote: post #41

I'm a bit confused. What is this notion of "pure randomness" that this article and many comments seem to be eluding to? Perhaps I'm just not using the same definitions of terms, but I thought a uniform distribution is still considered random.

> Perhaps I'm just not using the same definitions of terms, but I thought a uniform distribution is still considered random. No, a uniform distribution is not evidence of randomness. Consider the digits 0 - 9 repeated endlessly: 0123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789 ... Uniformly distributed? Yes. Random? No. > What is this notion of "pure randomness" tha…

>Uniformly distributed? Yes. Random? No.

I think you're fudging what is supposed to be uniform here. In your example, the unigrams (i.e. single digits) may be uniform, but the n-grams for n > 2 are not.

Post reply on HN