Random Number Questions

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This topic contains 23 replies, has 9 voices, and was last updated by  DrBob 3 years, 1 month ago.

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  • #4437

    Unseen
    Participant

    1) Is ANYTHING truly random? Or does randomness mean nothing more (or less) than unpredictability?

    2) My friend declares he’s invented a random number generator.

    2a) Is a random number generator an oxymoron?

    2b) The machine generates a series of 9’s and has been doing nothing but 9’s for days. After how many 9’s can it be concluded that something is wrong with his machine? Remember, to believe that what came before in a random series has any influence on future random outcomes is called The Gambler’s Fallacy. Given a truly random system, is a continual series of one number an impossible outcome? and given that mathematically infinite series are not just possible but inevitable, surely an ongoing series of 9’s is one such possible series, is it not?

    As usual, just pondering strange things. Frittering away my last days on Earth when I could be doing something useful.

    • This topic was modified 3 years, 2 months ago by  Unseen.
    #4440

    jakelafort
    Participant

    Seems like issue of whether anything is truly random is reformulation of determinism.  If effect follows cause in an unbroken chain then nothing is random. But what of a “beginning”? Perhaps that is random.  The failure to grasp the nature of reality has no apparent bearing on issue of random or determined. (intentionally avoiding quantum physics)

    It is funny how the word random is used in common parlance. “Oh he was just some random guy.” How is he any more or less random than the egotistic speaker? Random is defined by an absence of connection to the speaker, rather like “Columbus discovered America.”

    The gamblers fallacy is a paradox. On one hand the flip of coin has no apparent relation to prior flips. After 6 straight heads, tails is no more likely than it otherwise would be. On other hand flip that coin 10,000 times and the score will be within a percent or so of 50/50.

    #4441

    I think it is an oxymoron. I wrote a program once to generate a “random” number in very basic “BASIC”. It would only have been about 10 lines of code in the “Go to until” format. The number it output was “any number that met the specified criteria of the program” which gave the appearance of it being random. If there was no code and numbers occasionally appeared on the screen then maybe it would be.

    If what it generates is pre-determined by a script or program then it cannot be random. Maybe it would be more feasible with a quantum computer that worked at speed measured in Planck Time or would that be too fast?  Just a random thought I had that was pre-determined by considering the topic.

    A girl once told me that ” her brother was just sooooo random” but I did not ask for an explanation.

    #4442

    Unseen
    Participant

    Reg, what about a program that generates each number from a different, constantly changing, and unrelated source? Even just two sources would guarantee that each number generated was generated in a way unrelated to the previous number in the series. More sources would be even better. I’m trying to think of sources that are constantly fluctuating quickly enough to serve as such sources, but I’m coming up dry. Maybe micro-fluctuations in temperature, for one thing.

    #4443

    Unseen
    Participant

    But, Jake, if someone were to write a coin flip simulation, and it generates a series of the same number or the same pattern over and over seemingly ad infinitum, how does one know when to decide the machine is broken? LOL As I pointed out, such a series is a technically possible, if illogical and implausible, series.

    #4444

    Reg, what about a program that generates each number from a different, constantly changing, and unrelated source?

    Is that not a rather rhetorical question? Is that not the same as saying a program that generates each number from a “random” number generator?

    Maybe if the coding in the machine that selects from the source is written to select the number at some point between “now and infinity” or requiring some property of the exponential half-life decay of an isotope is met. (I don’t think that necessarily makes it pre-determined if it is not measured beforehand).

    If the machine knows when to predict the random number it lends predictability to the process and therefore it is a deterministic selection. Once we know something about the process of how the number is generated we are observing information about it and that removes any chance of uncertainty from it.

    I think that if it is possible then we will only find the answer in the quantum world where unpredictability reigns.

    #4445

    Unseen, this is a very good question. It is starting to bug me now! I will introduce it the next time I am in a “Freewill Vs Determinism” debate. It gets as close to the essence of the issue as anything I have considered previously. It will compel those in the Freewill camp to consider the problem from a different perspective.

    #4446

    _Robert_
    Participant

    Algorithms all generate pseudo-randomness. Thermal noise and background radio signal noise are very much random signals.

    #4447

    Unseen
    Participant

    Algorithms all generate pseudo-randomness. Thermal noise and background radio signal noise are very much random signals.

    So, it seems using the “noise” you proposed, it seeems that, paradoxically, you could use a deterministic algorithm to generate a truly random series of numbers.

    #4448

    Unseen
    Participant

    Unseen, this is a very good question. It is starting to bug me now! I will introduce it the next time I am in a “Freewill Vs Determinism” debate. It gets as close to the essence of the issue as anything I have considered previously. It will compel those in the Freewill camp to consider the problem from a different perspective.

    Well, yeah. It matters little if the cause of one’s actions is the result of a deterministic series going all the way back to the inception of the physical laws we know today, or if the cause is some “random” subatomic event. The human action is caused by something prior that wasn’t contributed by the human being, either proximately or at some earlier time. No real freedom there.

    #4449

    Unseen
    Participant

    If the machine knows when to predict the random number it lends predictability to the process and therefore it is a deterministic selection.

    Robert proposed using noise, which is unpredictable. Of course, once you plug it into the algorithm, from then on it’s deterministic, but the value derived from the noise is a truly random value and would be unpredictable, would it not?

    #4450

    DrBob
    Participant

    @unseen, I’m stuck on the “frittering away my last days on Earth” comment you made.   Is something up?  If so, I’m very sorry to hear it.

    1) It depends what you mean by “truly random”.  I believe the mathematicians have a very specific definition for that; indeed I believe there are several different classifications of randomness.   For ordinary people, I suspect a good working definition is “unpredictable and without any accessible underlying structure or trend.”

    I would argue that as far as we are able to measure any number of quantum phenomena are “truly random”, albeit within a well-defined distribution.

    2) Digital random number generators typically use algorithms that create complexity, i.e. that show sensitive dependence on initial conditions, or what is often termed “chaos”.  These require a seed that sets those initial conditions, and they are deterministic for any given seed.

    Usually what’s done is the seed is derived from some physical process within the computer.   One method often used is to be running a system clock counting in nanoseconds, and then take the lowest digits on the clock captured when the last keyboard key was pressed or the last mouse button was clicked.   That is generally a sufficiently random seed for all practical purposes, but obviously is still not “truly” random.

    2a) Well, if not an oxymoron it’s at least very difficult to do macroscopically.  I believe I read that even the ping-pong-ball thing that American lotteries use to generate lottery numbers can be shown not to be truly random because of the small differences in the mass of each ping pong ball.

    2b) This just depends on how sure you want to be about it.  In traditional parametric statistics, researchers arbitrarily set a 5% chance as being too small to worry about.   So when the chance of getting a series of 9’s of a certain length falls below 5%, we conclude that’s probably not due to random chance.   Of course, as you say, if you try enough times you will get a series of 9’s of any length so it’s important to test only once. Two 9’s in a row should do it.  😉

    [Edited for @Reg: It’s an interesting thought with regard to free will/determinism.   In the other direction, it’s also an interesting thought with respect to evolution and “random” mutations. 😉  Of course as far as we know the QED processes that underlie such things really are truly random, at least until we get into the speculations about time reversible interactions. 8-*} ]

    ——

    Anyways, thought I would comment just to see how you were doing and if you were OK.  It seems the TA site has disappeared while I was away, and this new one has the site rules that don’t allow old professors like me around, but wanted you to know I cared.

    Bob

     

    • This reply was modified 3 years, 2 months ago by  DrBob.
    #4452

    Unseen
    Participant

    Anyways, thought I would comment just to see how you were doing and if you were OK.  It seems the TA site has disappeared while I was away, and this new one has the site rules that don’t allow old professors like me around, but wanted you to know I cared.

    I have a job now and only two very valuable days off, this being the second one this week, so I no longer have the time to answer very long posts. At most, I just toss a comment or two into the ring.

    My health is about as good as a (nearly) 71 year old type 2 diabetic can expect. I found a small lump under the skin of my left arm recently and looking at my back in the bathroom mirror, using a hand mirror, I see a couple things that need to be assessed as well. Kaiser doesn’t seem to think it’s important enough to get me into see a dermatologist soon, so I have an appointment in mid-October.

    Other than that, the ticker is working fine and my blood pressure isn’t sky high. Neither is my cholesterol.

    I should last a little longer.

    #4453

    Unseen
    Participant

    In traditional parametric statistics, researchers arbitrarily set a 5% chance as being too small to worry about.   So when the chance of getting a series of 9’s of a certain length falls below 5%, we conclude that’s probably not due to random chance.

    Is that a “law of statistics,” a “rule-of-thumb,” simply a behavior one observes in statisticians, or what? What is the basis for that?

    #4454

    Unseen
    Participant

    Thermal noise and background radio signal noise are very much random signals.

    What does that mean? How can anyone know that? Or are we back to “as far as we’ll ever know…”?

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