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When a Random Poll Becomes a Monte Carlo Simulation
Mathematics Post #2731, on Feb 8, 2021 in TG

When a Random Poll Becomes a Monte Carlo Simulation

Why is this Mathematics meme funny?

Level 1: Evenly Spread Birthdays

Imagine you have three jars and a huge bag of multicolored candies. You start dropping candies randomly into the jars, one by one. If you drop enough candies, you’ll notice something interesting: all three jars end up with about the same number of candies. That’s basically what happened in this picture, except with people’s birthdays. They asked a big group of people to pick which part of the month their birthday falls in (beginning, middle, or end of the month). Because there were so many people answering, the groups turned out almost exactly equal in size. It’s funny and satisfying because no one rigged it or planned it that way – it just naturally came out super even. It’s like throwing a bunch of dice and getting an almost perfect split of results: it feels a little magical! The humor here is that a simple internet poll accidentally did a little science experiment, and the randomness of everyone’s birthdays created a beautifully fair, even result. In plain terms, it shows that with lots of people, birthdays are pretty much evenly spread out – and seeing that happen by chance makes us smile.

Level 2: Uniform Birthday Spread

Let’s break down what’s happening in simpler terms. The meme shows the results of a social media poll where lots of people answered the question, “What day is your birthday on?” Instead of making users type their exact day, the poll grouped days into three ranges: 1-10, 11-20, and 21-31 (these are the day-of-month bins). After 3,551 people voted, the number of votes in each range was almost the same. For example, roughly:

  • Days 1–10: about 1186 people have birthdays in this range
  • Days 11–20: about 1202 people have birthdays in this range (the screenshot shows this option selected)
  • Days 21–31: about 1163 people have birthdays in this range

Those counts are nearly identical, which is surprising at first glance. Why is that cool or funny? Because it suggests that birthdays are pretty evenly spread out across the month. In other words, it’s showing an approximately uniform distribution of birthdays by date. A uniform distribution means every day is about equally likely for a birthday (at least when grouped in chunks like these). We expect some variation by chance, but here each bin got around one-third of the votes – a very even data visualization of birthday frequencies!

Now, what’s this about Monte Carlo? In data science, a Monte Carlo simulation is a fancy term for an experiment where we use a lot of random samples to figure something out. It’s named after Monte Carlo, the famous casino city, because it involves randomness and repeated trials (like rolling dice or spinning a roulette wheel many times). Typically, if we want to know how something is distributed or what the chances are for different outcomes, we could simulate it on a computer by generating a bunch of random data. Here, the “random data” came from real people’s birth dates. Each person voting is like one random draw of a birthday. When thousands of people answer, you’ve essentially done a random_sampling of thousands of birth dates from the population.

What the meme highlights is that this random sampling gave a very balanced result. It’s as if someone ran a computer simulation to sample, say, 3000+ random birthdays and grouped them: you’d expect roughly equal numbers in each group of ten days. And indeed, the poll results came out super close to equal. This accidental poll essentially performed a Monte Carlo experiment without the poll creator intending it. It’s a bit of relatable humor for data folks because it shows a real-world example of a concept we often explain with theory: given enough random samples, the observed frequencies will match the expected probabilities. Everyone’s birthdays, taken together, became a mini science experiment confirming that birthdays don’t all cluster on certain dates — they’re spread out.

To put it more concretely: imagine writing a short program to simulate random birthdays and count them. It would look something like this:

import random

# Simulate 3551 random birthdays (day 1 through 31 for simplicity)
days = [random.randint(1, 31) for _ in range(3551)]

# Count how many birthdays fell in each range: 1-10, 11-20, 21-31
counts = [0, 0, 0]
for d in days:
    if d <= 10:
        counts[0] += 1
    elif d <= 20:
        counts[1] += 1
    else:
        counts[2] += 1

print(counts)  # e.g., output might be [1165, 1190, 1196] – all pretty close!

This code generates 3,551 random “people” and their birthdays, then groups them. A typical output might be something like [1165, 1190, 1196] for the three bins, which is indeed very close to equal – just like the poll. The meme basically shows that accidental_statistics in the real world matched what this little script would do! For a junior developer or someone new to data science, the takeaway is: if you ask a lot of people a question where the answers are truly random (like what day of the month they were born), the overall results will even out nicely. That’s why the poll’s evenly split result is both funny and cool – it visually proves a fundamental idea in statistics without any fancy setup. It’s a bit like stumbling onto a science experiment result while you were just browsing social media.

Level 3: Monte Carlo IRL

For seasoned data scientists and engineers, this meme hits like a jackpot of statistical humor. The image shows a poll asking “What day is ur birthday on,” with thousands of responses divided into three buckets (days 1–10, 11–20, 21–31). Astonishingly, each bucket has about ~1.2k votes – essentially an even split. This is hilarious and satisfying because it’s Monte Carlo IRL (In Real Life): a random crowd of social media users unintentionally performed a massive random experiment. In data science, we often run Monte Carlo simulations – generating tons of random data – to confirm expected outcomes or approximate solutions. Here, instead of a computer spitting out random numbers, real people’s birthdays served as the random draws, and the outcome aligns beautifully with expectation. It’s the kind of result you’d show in a DataVisualization workshop: a perfectly balanced histogram of birthdays by date range. The meme’s top text “I love Monte Carlo” underscores the nerdy joy – it’s poking fun at how a mundane poll ended up confirming a statistical law.

Think about the shared experience this reflects: anyone who’s done statistical analysis or played with large datasets knows that as sample size grows, patterns emerge clearly. Birthdays are a classic example – aside from minor seasonal or calendar biases, they’re pretty random across the days of the month. By binning the days into three groups, the poll essentially created a mini birthday histogram, and the bars came out almost equal height. That’s as expected by theory, but seeing it happen organically is like witnessing a little data-science magic trick. It’s similar to flipping a fair coin 1000 times – you know you should get about 500 heads and 500 tails, but if you actually get, say, 502 heads and 498 tails, you still feel a bit of awe at how evenly chance played out.

In the meme, each option’s count is within a few percent of the others (1186 vs 1202 vs 1163 votes). For data nerds, this accidental accuracy is both comical and gratifying. It’s comical because accidental_statistics like this rarely line up so neatly – nobody set out to perform a formal experiment, yet the crowd’s random behavior produced textbook-like data. It’s gratifying because it reaffirms our trust in large numbers: even a chaotic social media poll can demonstrate the principles we use in simulations and models. It’s as if the internet collectively rolled thousands of dice and got an eerily perfect distribution. In a world where so many polls are skewed or unscientific, this one ended up being a pure, unbiased sampler of human birthdays. That irony isn’t lost on the data science community: DataScienceHumor often points out when real-world data does something wonderfully predictable for a change.

In short, experienced folks recognize the joke: an online poll “accidentally” did a Monte Carlo simulation of birthdays. It highlights the uniform distribution of birthdays in a simply binned format and reminds us how robust random sampling is. The humor lives in that intersection of trivial social media behavior and high-level math concept – a kind of “so random it’s actually statistically perfect” situation. And yes, we genuinely find it cool – we’re the kind of people who actually do love Monte Carlo (the method, not just the casino)!

Level 4: Law of Large Polls

At the deepest level, this meme is a love letter to probability theory in action. The social media poll unintentionally demonstrates the law of large numbers and a textbook Monte Carlo simulation outcome. In a Monte Carlo method, we rely on repeated random sampling to approximate some statistical result. Here, each poll participant’s birthday acts like one random sample from an assumed distribution of all birth dates. If birthdays are (roughly) equally likely on any day 1 through 31 (a uniform distribution over the days of a month), then with enough samples the frequencies will converge to equal proportions. This is exactly what we see: out of 3,551 responses, the votes split almost perfectly among the three day-range bins. The probability of being born in days 1–10 is about $\frac{10}{31}$, in 11–20 is $\frac{10}{31}$, and in 21–31 is $\frac{11}{31}$ (since that bin covers 11 days). For large $N$, a multinomial distribution with these probabilities yields counts that concentrate tightly around $N \times p$. In fact, the expected counts for 3551 people would be around 1145, 1145, and 1261 for those three bins (given 11 days in the last bin), and the observed counts (1186, 1202, 1163) are impressively close to this ideal. The slight differences (dozens off from exact equality) are just normal random fluctuations – statistically, a spread of a few dozen in each bin is well within one standard deviation for $N\approx3500$. In other words, the outcome converges to uniformity with only minor deviation, illustrating how Monte Carlo simulations become more accurate as sample size grows (error shrinking on the order of $1/\sqrt{N}$). It’s delightful because this poll is effectively a stochastic experiment run by unwitting participants. The Monte Carlo method, famously named after the casino city Monte Carlo due to its gamble-like random trials, is being accidentally carried out by thousands of people responding to a casual question. The result? A near-perfect empirical distribution of birthdays. Statisticians and mathematicians can’t help but grin at how random_sampling by an online crowd so cleanly validates theory – it’s as if the social media world momentarily obeyed the equations of an introductory stats textbook.

Description

The image displays a large, bold caption, 'I love Monte Carlo,' above a screenshot of an online poll. The poll asks, 'What day is ur birthday on' and provides three options for ranges of days: '1-10,' '11-20,' and '21-31.' The results show a remarkably even distribution of votes across the options: 1,186k for 1-10, 1,202k for 11-20, and 1,163k for 21-31, with a total of 3.551 votes indicated (note: there is a visual discrepancy between the 'k' in the options and the total, but the distribution is the key). The joke is a clever reference to the Monte Carlo method, a class of algorithms that relies on repeated random sampling to obtain numerical results. The near-uniform distribution of birthdays across a large population is a perfect real-world example of the statistical principles that underpin Monte Carlo simulations. For anyone in data science, scientific computing, or quantitative fields, the image is a humorous nod to seeing a fundamental mathematical concept emerge organically from seemingly trivial data

Comments

60
Anonymous ★ Top Pick A junior data scientist sees this and says, 'Cool, a uniform distribution.' A senior data scientist sees this, mutters 'PRNG seems solid,' and starts wondering if they can use the timestamps of the votes to estimate pi
  1. Anonymous ★ Top Pick

    A junior data scientist sees this and says, 'Cool, a uniform distribution.' A senior data scientist sees this, mutters 'PRNG seems solid,' and starts wondering if they can use the timestamps of the votes to estimate pi

  2. Anonymous

    We spent two sprints validating our PRNG; marketing’s “What day is your birthday?” poll hit χ² ≈ 0 before lunch - Monte Carlo-as-a-Service, powered by 3,551 unsuspecting users

  3. Anonymous

    Finally, a production environment where Monte Carlo actually converges to the expected distribution - turns out 3,551 random internet users are more reliable than our pseudo-random number generators, though I'm still waiting for someone to file a bug report about February having fewer days

  4. Anonymous

    When your production data accidentally validates a CS theory better than any academic paper ever could. 3,551 developers just proved that birthdays follow a uniform distribution - turns out the real Monte Carlo simulation was the friends we polled along the way. Now if only our load balancers distributed traffic this evenly

  5. Anonymous

    I love Monte Carlo too: run a poll to “simulate” birthdays, ignore that 21 - 31 has a bigger state space, and ship a date picker with a 4% bias - see you at the leap-year postmortem

  6. Anonymous

    Nothing says “data‑driven” like a Monte Carlo poll with 10/10/11‑day buckets and a locale‑broken “k” - PM calls it significant, we ask if anyone divided by bin width

  7. Anonymous

    Classic Monte Carlo: ideal uniform RNG in theory, Reddit-biased convergence to mid-month in prod

  8. @Box_of_the_Fox 5y

    I guess it's this: https://en.m.wikipedia.org/wiki/Monte_Carlo_method

  9. @GTRst 5y

    Actually it's a normal (Gauss) distribution

    1. @unituni 5y

      Yep finally smbody wrote that

      1. @digital_insanity 5y

        And made an error Oopsie

    2. @digital_insanity 5y

      Normal distribution has peak and 2 lows in both sides This is uniform distribution

      1. @unituni 5y

        Nope actually first and third options are those lows u are talking about so this is normal distribution it's just quite kinda low overall

        1. @GTRst 5y

          +1

        2. @digital_insanity 5y

          Concerning amplitude of each portion small variation may be statistically insignificant

          1. @unituni 5y

            So it as well may be a normal distribution))

            1. @digital_insanity 5y

              Engineers don't operate with "may be"s)) There are exact formulas how to distinguish distributions by variety of criteria And for all I've learned during metrology&statistics course that's not looking like Gauss)

              1. @unituni 5y

                That's not uniform as well)

                1. @digital_insanity 5y

                  Take 100k+ survey and see yourself how BD are distributed, lol </thread>

                  1. @unituni 5y

                    And finally, as I found out from your russian texts, you lack not only knowledge in probability&statistics but also have problems with sense of humor and communication culture so yeah кек мда you are пиздец инженер))) btw we don't need 100k responses 3k is representative enough) u r welcome)

                    1. @digital_insanity 5y

                      Тоесть все свелось к: "Это ж просто мем, ты не умеешь в юмор" Апелляции к культуре общения (будто комуто не насрать на нее) и телепатия по поводу знаний в статистике "Ну такто там будет равномерное распределение, но в этом то случае мы видим же что чиселки разные на картинке!!" А, ну и да, продолжать дальше отвечать на англ человеку знающему русский, это вообще за гранью)

  10. @unituni 5y

    Anyway well we are talking about three columns so that's kind of incorrect a little bit in terms of analysis)

    1. @unituni 5y

      .

  11. @napLord 5y

    Каким образом число родившихся людей по дням месяца у вас нормальное распределение? ебаный стыд. Может еще число родившихся людей по дню года у вас нормальное распределение?

    1. @digital_insanity 5y

      Да смотрю тут пиздец инженеры собрались

      1. @unituni 5y

        /

  12. @digital_insanity 5y

    Определяют распределения по 3 точкам и с уверенностью находят нормальное, хотя тут его нет и не может быть

  13. @digital_insanity 5y

    Кек мда

  14. @unituni 5y

    Well we were discussing these three columns on the meme and not the function of human birthdays (f(date)) so u r taking it too serious)) if we would like to analyze all 365 days for sure it will not be neither uniform nor normal distribution, but closer to the second one because there is some low peaks on the end of the spring-summer, likely a composition of a few normal distributions)

  15. @unituni 5y

    Those peaks locations through the year depends on tons of different factors including possibility of unexpected ones like pandemic) And about the dates distr. on meme - it's tricky and yeah, in general it will be uniform distribution but in this particular case those three columns can form (if we can say so lol, as I mentioned before it's kinda incorrect approach) low-peaked normal distribution (we still have those 3.4% of difference, as well as they may not so we cannot tell exactly because we don't know a lot of details)

  16. @unituni 5y

    well i know google translate service)

  17. @digital_insanity 5y

    Ждем-с что будет дальше

  18. @unituni 5y

    so your only defense is that it can be statistical error? well, i`ll be waiting for your proof using those formulas you were talking about) Ive said enough and your message just confirms all that i said above)

    1. @RiedleroD 5y

      my god, calm down

      1. @unituni 5y

        y u dont say same thing to the guy who thinks its cool to demonstrate his own ego by writing offensive phrases

        1. @RiedleroD 5y

          …I can't speak russian man. Even so, it's the internet. Don't get offended, that's just pointless.

  19. @unituni 5y

    i cant too

  20. @unituni 5y

    but still it looks like he (or she) expected that i won't find out)

    1. @RiedleroD 5y

      find out what?

  21. @unituni 5y

    that he says about people who got in the discussion that they`re shitty engineers

    1. @RiedleroD 5y

      so what?

  22. @unituni 5y

    well i tried to explain my point of view so that was kinda disrespectful but well at least i feel my satisfaction in the end thankfully to my knowledge not the curses)

    1. @RiedleroD 5y

      ok so I just translated his texts with google translate, and maybe I'm missing something, but from my point of view, you're just being obnoxous

  23. @o6m0o9m 5y

    Omg, it was just a joke Still you are not right At first, it's discrete so there are no "normal" or "uniform" distributions in here At second, it's even not discrete-uniform in the limit (there are less 29-31 days in months)

    1. @unituni 5y

      yep exactly!

      1. @RiedleroD 5y

        then where's the problem?

        1. @unituni 5y

          ''Yes, I look here asshole engineers gathered''

          1. @RiedleroD 5y

            translates to "yes, I look here fucking engineers gathered" on my machine but even if he called you an asshole… get over it, geeze

    2. Deleted Account 5y

      Your first point isn't really relevant but your second one is true

      1. @o6m0o9m 5y

        It's matter only in a context of being "statistically correct" which was mentioned earlier

  24. @unituni 5y

    here)

  25. @unituni 5y

    it was his message

  26. @unituni 5y

    well i already got) the last ten minutes i was exaplaining to you why i answered him but u still dont see the problem

  27. @RiedleroD 5y

    no

  28. @unituni 5y

    and i will get over it too))

    1. @RiedleroD 5y

      then don't complain please

  29. @unituni 5y

    i wasn't going but ok

    1. @RiedleroD 5y

      you were the whole time but ok

  30. @unituni 5y

    what?

  31. @gammapopolam 5y

    привет я россия

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