Choose a random number.

[signerror]

Make sure it is really random. No cheating!

[Moonbear]

Can you really "choose" a random number?

[neu]

You can't cheat, but you also can't "choose"; lose, lose situation

[BobG]

I don't like this game. There aren't enough choices. I wanted to pick 1729.03.

[Jimmy Snyder]

Before I vote, I would like to clear up one thing. Is 18 a random number?

[neu]

Before I vote, I would like to clear up one thing. Is 18 a random number?

18 is as random as 7

[DaveC426913]

I am going to bet that you will find a non-random distribution. There will be a statistically significant lack of hits at the ends as well as at the middle, resulting in a double-humped graph.

When asked to choose a number between 1 and 10, a more-than-average number of people will choose 3 or 7 because, psychologically, those numbers are more "hidden".

[Jimmy Snyder]

I am going to bet that you will find a non-random distribution. There will be a statistically significant lack of hits at the ends as well as at the middle, resulting in a double-humped graph.

When asked to choose a number between 1 and 10, a more-than-average number of people will choose 3 or 7 because, psychologically, those numbers are more "hidden".
I remember hearing that you can tell the difference between a sequence of 1's and 0's generated by a pseudo-random generator, and one generated by a person. Apparently, when people generate a sequence, they avoid long runs.

[CRGreathouse]

Four is a random number: it was chosen by a fair die roll.
http://xkcd.com/221/

Myself, I used the seconds digits of the current time, mod 20.

[CRGreathouse]

I am going to bet that you will find a non-random distribution. There will be a statistically significant lack of hits at the ends as well as at the middle, resulting in a double-humped graph.

When asked to choose a number between 1 and 10, a more-than-average number of people will choose 3 or 7 because, psychologically, those numbers are more "hidden".

I would have guessed the same thing -- but it seems that we have just the opposite in the distribution so far.

Of course, not so much as to make it fail a chi-square: 14.67 vs. the 19.68 needed to reject at 0.05 level with 11 degrees of freedom.

[TheStatutoryApe]

I closed my eyes moved the cursor around in the vicinity of the numbers and then clicked. It took a couple tries.

[rootX]

Can you really "choose" a random number?

I closed my eyes and moved my cursor to one of the numbers (it was 7). Initially, I wanted to choose 4.


I thought people wouldn't pick numbers near boundary because they appear less random but I guess I am wrong. (I went towards to middle to make it look like random)

[rootX]

I closed my eyes moved the cursor around in the vicinity of the numbers and then clicked. It took a couple tries.

I also did the same thing :)

[Moonbear]

I am going to bet that you will find a non-random distribution. There will be a statistically significant lack of hits at the ends as well as at the middle, resulting in a double-humped graph.

When asked to choose a number between 1 and 10, a more-than-average number of people will choose 3 or 7 because, psychologically, those numbers are more "hidden".

I would predict that if you put this poll up on any other forum aside from PF, that is precisely what you would see. I think that the folks here at PF are too aware of these patterns and will actually try to break them. I'm curious to see what pattern might instead emerge...maybe the mirror image of what you were predicting.

[DaveC426913]

I would predict that if you put this poll up on any other forum aside from PF, that is precisely what you would see. I think that the folks here at PF are too aware of these patterns and will actually try to break them.Guilty. :biggrin: I chose 1.

[BobG]

I used the random number scale on my Schmendrolog slide rule. This is a great military slide rule, as it's resistant to EMP.

The Amazing Schmendrolog...

This Polish slide rule (manufactured circa 1973) featured such groundbreaking slide rule innovations as the 'RND' scale (random number generator) and the famous blank area on the back for writing intermediate values and phone numbers.

In fact, this rule was the first to feature reverse polish notation, an important step in modern computing technology.

http://www.sphere.bc.ca/test/frankenrules/195-scales2.jpg

http://www.sphere.bc.ca/test/frankenrules/194-schmend.jpg

[WiFO215]

I closed my eyes moved the cursor around in the vicinity of the numbers and then clicked. It took a couple tries.
I did the same thing and ended up clicking on the advertisements. :shy:

[OAQfirst]

I'm the first to pick 10. I'm awesome!

[LowlyPion]

I chose a time of day in seconds, divided by 20, and voted the remainder.

Seems a random choice enough for me.

[drizzle]

I wanna choose 7 could I:biggrin:, now randomly picking I get 6 [apparently the first to pick it]


can I ask, what's the point of this thread?

[lisab]

can I ask, what's the point of this thread?

Well I don't know what the OP's intent was, but for me, it's just pure, pointless, geeky entertainment :smile:.

[Borek]

No point IMHO.

No idea what should I vote for. I like 7 as well, but - as I like it - it is not random.

[drizzle]

No point IMHO.

No idea what should I vote for. I like 7 as well, but - as I like it - it is not random.



just took the words out of my mouth...







hey I've just say so even before you do:tongue:.

[drizzle]

Well I don't know what the OP's intent was, but for me, it's just pure, pointless, geeky entertainment :smile:.


really...




I don't know why the hell I feel stupid now!
:rofl:

[moose]

I would predict that if you put this poll up on any other forum aside from PF, that is precisely what you would see. I think that the folks here at PF are too aware of these patterns and will actually try to break them. I'm curious to see what pattern might instead emerge...maybe the mirror image of what you were predicting.

Haha exactly! I made sure to not choose 3 or 7.

[EnumaElish]

The computer time is (was) 5:40 = 1740 hours. Added digits until they fall into the 1-20 range: 1+7+4 = 12. I'm amazed to see a (more or less) uniform distribution.

[flatmaster]

I was expecting 7 and 13 to pop out. Lucky and unlucky.

[flatmaster]

Also, were just over n=30, so now we're stastically significant.

[AUMathTutor]

Let's compare to a pseudorandom number generator...

1 : 4 0
2 : 1 1
3 : 0 2
4 : 3 1
5 : 2 3
6 : 3 3
7 : 7 5
8 : 1 3
9 : 1 5
10 : 2 0
11 : 1 2
12 : 1 2
13 : 2 2
14 : 1 4
15 : 1 2
16 : 2 1
17 : 3 1
18 : 4 2
19 : 1 1
20 : 2 2


Here's the code I used...


#include <iostream>
#include <cstdlib>

using namespace std;

int main()
{
const int N = 42;

int freq[20] = {0};

srand(time(0));

for(int i = 0; i < N; i++)
{
freq[ rand() % 20 ] ++;
}

for(int i = 0; i < 20; i++)
{
cout << (i+1) << " : " << freq[i] << endl;
}

return 0;
}


Ironically, the human one seems to be more "random" than the pseudorandom one.
This leads me to think that people are cheating.

[flatmaster]

According to your program, 7 is lucky!!

[ExactlySolved]

I let Mathematica choose for me:


In[1] := RandomChoice[Range[20]]

Out[1] := 13

[flatmaster]

Mathematica is Unlucky!!

[LowlyPion]

Ironically, the human one seems to be more "random" than the pseudorandom one.
This leads me to think that people are cheating.

Run your program more times then.

Eventually it should yield an instance that agrees with 30 physicists typing on keyboards selecting numbers between 1 and 20.

When you document congruence, you will have your proof that it must be random.

[ExactlySolved]

Mathematica is Unlucky!!

Haha, anyone can generate a random choice from this list using Wolfram|Alpha, just type in:


RandomInteger[20]


or


Floor[20 Random[]]+1

[BobG]

A rare thing happened at work today. Every month we have birthday cake to celebrate everyone born in that particular month. Today we had cake, but it turned out that none of the 66 employees in our building had a June birthday (the odds against that happening are about 311-1).

Coincidently, the music to "Happy Birthday to You" was written by Mildred J. Hill, who was born in June and died in June. (With no birthdays to celebrate, we had to do something while we ate our cake, so we had birthday trivia.)

[LowlyPion]

(With no birthdays to celebrate, we had to do something while we ate our cake, so we had birthday trivia.)

Apparently so.

Happy Birthday Mildred then.

[CRGreathouse]

A rare thing happened at work today. Every month we have birthday cake to celebrate everyone born in that particular month. Today we had cake, but it turned out that none of the 66 employees in our building had a June birthday (the odds against that happening are about 311-1).

About 288:1 based on the number of days in that month and that month's frequency:
http://www.maa.org/mathland/mathtrek_11_23_98.html

[QuantumPion]

I just wiggled my mouse around wildly with my eyes closed and picked the radio button closest in vertical position to where it stopped at. 6!

[drizzle]

since the talk is about [bizarre] numbers, did you ever felt like you’ve been chased by a number!! sounds funny I know, but I mean [personally], where ever I look, I see the number 42, the time is always [something:42], my academic number was 42, every film I watch points out that number [like, street 42, apartment 42…], what makes this more creepy to me
now, is the number I picked randomly here is 6, unlike the number I would like to pick which is 7…



but hey 6*7=42:surprised

[neu]

Start another thread, exactly the same but ask people to "choose a non-random" number then subtract that distribution from this one and you have a random distribution. easy

[Feezik]

6, 16,

[Borek]

I just wiggled my mouse around wildly with my eyes closed and picked the radio button closest in vertical position to where it stopped at. 6!

Not random at all. Most likely you ended around the starting position, where your hand was at rest.

[Borek]

About 288:1 based on the number of days in that month and that month's frequency:
http://www.maa.org/mathland/mathtrek_11_23_98.html

Interesting, I believe I have seen similar list of birth frequencies for Poland back in eighties, and there was a surge around April/May, that is, 9 monts after summer vacations. Could be these were data before contraception became reasonably available here.

[DaveC426913]

Not random at all. Most likely you ended around the starting position, where your hand was at rest.
It is more random than the rest of us.

[Moonbear]

It is more random than the rest of us.

I'm not sure of that. When the sequence of numbers remains in the same order, and you have some sense of how much you're moving the mouse up and down, you're pretty likely to land quite close to where you intended to land.

[BobG]

since the talk is about [bizarre] numbers, did you ever felt like you’ve been chased by a number!! sounds funny I know, but I mean [personally], where ever I look, I see the number 42, the time is always [something:42], my academic number was 42, every film I watch points out that number [like, street 42, apartment 42…], what makes this more creepy to me
now, is the number I picked randomly here is 6, unlike the number I would like to pick which is 7…



but hey 6*7=42:surprised

If you drill a hole from the North Pole, through the center of the Earth to the South Pole, and then drop a ball into the hole, how many minutes will it take for the ball to reach the surface at the South Pole (disregarding any friction from the air, etc)?

Why was the Mad Hatter mad?

(Just trying to fuel your obsession).

[drizzle]

If you drill a hole from the North Pole, through the center of the Earth to the South Pole, and then drop a ball into the hole, how many minutes will it take for the ball to reach the surface at the South Pole (disregarding any friction from the air, etc)?

Why was the Mad Hatter mad?

(Just trying to fuel your obsession).


:cry::cry::cry:

[DaveC426913]

I'm not sure of that. When the sequence of numbers remains in the same order, and you have some sense of how much you're moving the mouse up and down, you're pretty likely to land quite close to where you intended to land.Yeah, I'm not saying it's a good method - but just picking a number can't be a good method either. I picked 1. How could that be random?

[Redbelly98]

Still working on my number, so far I'm up to the 247th digit.

[AUMathTutor]

How can you really pick a random number? It seems like most of the methods we've been using are biased.

My random number generator was biased. Wiggling the mouse around is biased. Taking the time and doing a modulus is biased.

[DaveC426913]

How can you really pick a random number? It seems like most of the methods we've been using are biased.

My random number generator was biased. Wiggling the mouse around is biased. Taking the time and doing a modulus is biased.

Yep.

[Loren Booda]

My guess was that, given the numbers 1-20, two digit prime numbers would intuitively and disproportionally be preferred as "random." Two digits numbers because they are more diluted over their implied range than one digit numbers (here 10-20 recalls 10-99), and prime numbers because we are less accustomed to using their factorization (thus evoking fewer interrelations than composite numbers on this list).

Just a guess.

[AUMathTutor]

How about this for a fair random process?

You grab a handful of sand. You then count how many grains of sand there are. Take the number and the remainder after dividing it by 20 should not be biased.

Here's my reasoning: the bounds aren't fixed on how many grains there can be. This means that there is no inherent bias in the range of values. You will usually get many more than 20 grains of sand, so the part that's actually deciding the outcome is sufficiently masked.

Are there problems with that?

[Sorry!]

Lol, just picked 10. Was thinking if I should force myself to pick a different number... I was thinking instead of 10 I should go for 1. Instead I just stuck with 10. I dont think it was random though... does 'random' actually occur in reality?

[Borek]

does 'random' actually occur in reality?

A far as we know - yes. How long does it take for a radioactive atom to decay?

[Office_Shredder]

A far as we know - yes. How long does it take for a radioactive atom to decay?

22 minutes

[Borek]

And the next one?

[Chi Meson]

And the next one?

Gosh, everyone knows about half-life, right? 11 minutes!

[Moonbear]

How about this for a fair random process?

You grab a handful of sand. You then count how many grains of sand there are. Take the number and the remainder after dividing it by 20 should not be biased.

Here's my reasoning: the bounds aren't fixed on how many grains there can be. This means that there is no inherent bias in the range of values. You will usually get many more than 20 grains of sand, so the part that's actually deciding the outcome is sufficiently masked.

Are there problems with that?

That would probably be pretty random...if you felt like sitting around counting grains of sand in a lot of handfuls of sand.

I want to offer some food for thought while we're playing with this thread. Statisticians love to tell people that assigning subjects to experiments needs to be done randomly. This is supposed to eliminate bias. But, does it?

Say I'm doing a study on some magic weight loss pill and am assigning volunteers for my study to one of two groups, magic weight loss pill or placebo.

I could choose to assign them to groups on some random basis (perhaps using a random number generator and all the odds go to one group and evens to another), or I could choose to put constraints on the group assignments that make it non-random, such as ranking their weights at start of the study and then matching pairs of similar weight people one to each group to get two similar (if not equal) sized groups with a similar distribution of weights of subjects in them.

At the end of using random assignments, I might end up with many more people in the placebo group and those assigned to the magic weight loss pill group might be all my most obese subjects who have a lot of weight to shed compared to my placebo group that has such skinny people they couldn't shed weight no matter what diet they were on.

Which is less biased?

[Borek]

Statisticians love to tell people that assigning subjects to experiments needs to be done randomly.

Not necesarilly. You may select your sample so that it is representative of the population and as random as possible within constrains.

[russ_watters]

Before I chose my answer, I looked at the poll results, then chose the number that had the most votes at the time...

[jobyts]

Doesn't quantum cryptography use pure random numbers (based on HUP)?

[Borek]

Before I chose my answer, I looked at the poll results, then chose the number that had the most votes at the time...

I did quite the opposite.

[Chi Meson]

Yeah baby! My random number's winning! Woo hoo! Way to go, yeah!

[BobG]

I'm kind of disappointed in my random number. I kind of like monogamous relationships with my numbers.

[LowlyPion]

I'm kind of disappointed in my random number. I kind of like monogamous relationships with my numbers.

It was bound to happen.

[Redbelly98]

Hey, wait, why are we obsessing about how we choose the number? As I interpret the poll instructions, "choose a random number", the OP has provided a list of random numbers that we are to choose from in any manner we see fit.

Now if the instructions had said "Randomly choose from the following list of numbers", that would be a different story.

:biggrin:

p.s. in all seriousness, I have picked 7 using Excel's random number generator.

[Office_Shredder]

Hey, wait, why are we obsessing about how we choose the number? As I interpret the poll instructions, "choose a random number", the OP has provided a list of random numbers that we are to choose from in any manner we see fit.


Ooh, nice catch. The ambiguity here could destroy the integrity of the results. We'll have to create an independent commission to investigate further

[LowlyPion]

Ooh, nice catch. The ambiguity here could destroy the integrity of the results. We'll have to create an independent commission to investigate further

We'll need a Random Number Czar then to mediate.

[Moonbear]

Hey, wait, why are we obsessing about how we choose the number? As I interpret the poll instructions, "choose a random number", the OP has provided a list of random numbers that we are to choose from in any manner we see fit.

Now if the instructions had said "Randomly choose from the following list of numbers", that would be a different story.

:biggrin:

p.s. in all seriousness, I have picked 7 using Excel's random number generator.

Ooh, nice catch. The ambiguity here could destroy the integrity of the results. We'll have to create an independent commission to investigate further

We'll need a Random Number Czar then to mediate.

:rofl: This is why I love PF and the people here so much. :biggrin:

Wow, there's a cluster of mentors all in the middle. Integral is the only mentor who broke away from the pack. Contributors seem to be more independent thinkers, with numbers chosen throughout the range. :biggrin:

[EnumaElish]

How about this for a fair random process?

You grab a handful of sand. You then count how many grains of sand there are. Take the number and the remainder after dividing it by 20 should not be biased.

Here's my reasoning: the bounds aren't fixed on how many grains there can be. This means that there is no inherent bias in the range of values. You will usually get many more than 20 grains of sand, so the part that's actually deciding the outcome is sufficiently masked.

Are there problems with that?Is "fine granular stuff from a burst stress ball" an acceptable substitute for sand?

[AUMathTutor]

As long as you don't use all of it... maybe?

[flatmaster]

My probability is a little rusty. What sort of discrete probability distribution would theoretically be expected here considering it was truly random? Poisson Distribution? A Bayesian analysis could tell us the probability that this data is actually a random distribution. Might do that later.

[qntty]

My probability is a little rusty. What sort of discrete probability distribution would theoretically be expected here considering it was truly random? Poisson Distribution? A Bayesian analysis could tell us the probability that this data is actually a random distribution. Might do that later.

If it was truly random, a uniform distribution would be expected, would it not?

[flatmaster]

If it was truly random, a uniform distribution would be expected, would it not?

For a sufficently large number of votes, it obviously would. However, for a small number of votes, there are outliers. Consider the first vote as your only data. A frequentist prospective would say that a random number between 1 and 20 is defined as that number.

[DaveC426913]

Is "fine granular stuff from a burst stress ball" an acceptable substitute for sand?:rofl:

[colonelcrayon]

my @numb = (1 .. 20);

my $num = int(rand(19));
print @numb[$num];
Perl does it for me. I got 9.

EDIT: This is what I get for approaching a simple problem with a solution already in my mind. It might make more sense to just print $num and ditch the array... :P

[Moonbear]

So, how do you know a number is generated randomly? Wouldn't even a so-called random number generator need to have some sort of rules to generate the numbers?

[jobyts]

So, how do you know a number is generated randomly? Wouldn't even a so-called random number generator need to have some sort of rules to generate the numbers?

A computer cannot generate pure random number. What computer generates is a pseudo random number. For most of the random number applications, pseudo random numbers are more suited than pure random numbers. Pure random numbers have very little applications.

[DaveC426913]

A computer cannot generate pure random number. What computer generates is a pseudo random number. For most of the random number applications, pseudo random numbers are more suited than pure random numbers. Pure random numbers have very little applications.You can start with a seed rather than using a system-generated randomizer.

[Moonbear]

A computer cannot generate pure random number. What computer generates is a pseudo random number. For most of the random number applications, pseudo random numbers are more suited than pure random numbers. Pure random numbers have very little applications.

So, still, how would you know if a number WAS a pure random number? Where do they come from and how would you recognize them?

[siddharth]

So, still, how would you know if a number WAS a pure random number? Where do they come from and how would you recognize them?

Maybe using a natural process which is random, like the decay of an atom. If there's geiger counter connected to a computer, and tracks the delay between individual decays.

There are also tests for randomness (http://csrc.nist.gov/groups/ST/toolkit/rng/index.html) which may give a pretty good idea of how random a sequence of numbers generated by a pseudo-random number generator are (although, these can easily fail). In fact, in my senior thesis, I have to perform a lattice monte-carlo simulation, and the pseudo-random number generator I use (http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/emt.html) has a period of 219937-1

[BobG]

My probability is a little rusty. What sort of discrete probability distribution would theoretically be expected here considering it was truly random? Poisson Distribution? A Bayesian analysis could tell us the probability that this data is actually a random distribution. Might do that later.

If it was truly random, you'd expect a uniform distribution.

If you ask humans to pick a random number from 1 to 20, you'd expect a spike at 17. 37 is an even more popular random number than 17 if the range is 1 to 100. The favorite random number from 1 to 10 is 7.

The question was asked to a non-typical audience. Some of the responders seem more proud of how they picked their random number than they are of the number they picked.

[CRGreathouse]

We have 87 responses so far, and the chi-square value, 94.63, is below the 95% threshold of 108.65.

We're still random!

[Redbelly98]

2 seems rather unpopular in this poll so far (1 out of 88 responses, 1.1%)