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How random is xkcd? (2015)

hardmath123.github.io

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Re: How random is xkcd? (2015)

#2
* Then, I fed them to the NIST Statistical Test Suite.

* I encourage you to play with the STS code.

* It also segfaults all over the place, which is actually very disturbing considering that it’s technically part of the US government’s computer security project.

Well, package that computes stats on number series to test variopus notions of randomness - it's not as if pwning the STS will let you play a game of nuclear war.

All the same, there's an exercise for any budding numerical programmers, read up on the suite, build it, run it, static analyse it, valgrind it, and iron a few wrinkles out.

https://csrc.nist.gov/projects/random-bit-generation/documen...

Got to be worth a humble brag in an application or two | make contacts in NIST.

Re: How random is xkcd? (2015)

#3
Kind of an aside to the nerd sniping happening here, but I think the fact that people complain about the random button is a sign that the feature isn’t doing what those people really want, even if it is doing what is advertised. Those people _want_ a button biased to return novel ones they haven’t read either in that session or across all time somehow, likely because they are using it to discover new comics.

Re: How random is xkcd? (2015)

#7
post #4

> a random stream of bits should have almost as many ones as zeros almost ??

I think this is the correct way to phrase it. Just because the probabilities of each are both 50% doesn't mean it's more likely than not to get the same number of ones and zeros. It would just mean you're equally likely to get a few more ones as you are to get a few more zeros. But the counts are unlikely to be very far apart.

Re: How random is xkcd? (2015)

#9
Using the formula in the article:

- Out of 1500 comics (at the time of the article), 45 random selections gives you a 48.656% chance of a duplicate, and 46 gives you a 50.196% chance.

- Out of 2873 comics (as of right now), 63 random selections gives you a 49.579% chance of a duplicate, and 64 gives you a 50.685% chance.

2929 comics is the most from which randomly selecting 64 will have a greater than 50% chance of having duplicates (50.00854657587404%).

Re: How random is xkcd? (2015)

#10
post #7
post #4

> a random stream of bits should have almost as many ones as zeros almost ??

I think this is the correct way to phrase it. Just because the probabilities of each are both 50% doesn't mean it's more likely than not to get the same number of ones and zeros. It would just mean you're equally likely to get a few more ones as you are to get a few more zeros. But the counts are unlikely to be very far apart.

But in absolute (not relative terms) the counts will tend to diverge over time.
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