▲ 14 r/math

Sequential rejection sampling over multiple finite sets

I've been thinking about a sampling problem that looks simple at first, but I'm not sure about its statistical properties.

Suppose we generate an infinite sequence of uniformly random integers from some finite universal set (U).

Instead of using that sequence directly, we build several different samples simultaneously. Each sample has its own acceptance rule (for example, allowed value range, uniqueness constraints, required sample size, etc.).

The algorithm is simply:

- read the next value from the common sequence;

- if it satisfies the constraints for sample A, append it there; otherwise discard it for A;

- continue until A is complete;

- do the same independently (starting from first position of U) for samples B, C, ...

Every sample is therefore produced by rejection sampling from the same underlying random sequence, rather than from independent random generators. Each individual sample should still be uniformly distributed over its own valid sample space. However, the samples themselves no longer appear to be independent because they originate from the same source sequence.

Is there an established probabilistic framework or name for this type of construction? It feels related to rejection sampling, but I haven't seen the multi-sample version discussed before. I'd be interested in any references or similar constructions.

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u/PleasantLow670 — 6 days ago

If the only available information is weak, should a decision-support system stay silent?

I've been thinking about an interesting design problem.

Imagine you're building a system that helps people make decisions under uncertainty. Sometimes it has plenty of useful information. Sometimes it has almost none.

Now imagine the only information available is something like: time of day, day of the week, a person's own historical behavior, previous outcomes from similar situations. None of these variables should be strong predictors by themselves. Any signal they contain is likely to be weak, noisy, and unstable.

So what should the system do?

One philosophy is: "If the evidence isn't strong enough, don't recommend anything." Another is: "Present weak signals transparently, explain their uncertainty, and let people decide how much weight to give them."

Personally, I find the second approach fascinating. Humans already rely on weak signals all the time: intuition, routines, superstitions, "today feels like a good day", recent experiences, emotional state. Those signals may not be objectively reliable, but they clearly influence decisions.

So why shouldn't a decision-support system expose weak statistical signals ... as long as it makes their limitations explicit?

I've been prototyping an experimental decision-support system around this question. It doesn't try to predict future outcomes or outperform probability. Instead, it records repeated decisions, tracks outcomes over time, and explores whether weak behavioral signals become more informative as data accumulates.

I'm genuinely interested in where people here would draw the line. At what point does a weak signal become useful enough to present? Or should decision-support systems remain completely silent until they have statistically compelling evidence?

If anyone here works on behavioral decision-making, choice architecture, or uncertainty, I'd genuinely appreciate your perspective. And if you'd like to participate in the experiment itself, I'd be happy to share how it works.

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u/PleasantLow670 — 8 days ago

The startup version of the chicken-and-egg problem

Everyone says "find your customer."

That makes perfect sense when you're solving a well-understood problem. But what if you built a tool and people keep finding uses for it that you never expected?

Imagine you invent the first hammer.

You create it because people are struggling to drive nails with rocks. So naturally, you think your users are people who need to drive nails.

Then people start using the hammer to break things apart. Or straighten bent metal. Or remove old boards. Or dozens of other things you never designed it for.

At that point, who is your customer? The people you originally built it for? Or the people discovering entirely new use cases?

This is something I've been struggling with recently.

The more feedback I get, the less certain I am that the original use case is actually the most important one. Part of me thinks the answer is simple: pick one audience and focus. Another part thinks that if you do that too early, you may accidentally ignore the most valuable application of your own product.

So I'm curious: How do you approach customer discovery when the product seems capable of solving multiple different problems for multiple different groups of people? Do you let the market teach you what the product is? Or do you force a narrow positioning early and ignore everything else?

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u/PleasantLow670 — 15 days ago

Built the product myself. Now I need a partner, but afraid to give away equity.

About 9 months ago I had an idea for a niche product and decided to build it myself. I'm not a mobile developer, but I have a strong software/architecture background, and with AI-assisted development I managed to go from idea to a working product and multiple releases.

The thing is: I now realize that building the product may have been the easy part. What I don't have is experience in growing a product, finding distribution, positioning, partnerships, fundraising, or scaling a business around it.

For the first time I'm seriously considering bringing in a partner who has experience in the industry and has already done what I'm trying to learn. But I'm struggling with the tradeoff.

I've invested hundreds of hours into this project. I know every corner of it. Giving away equity feels expensive. At the same time, keeping 100% of something that never grows may be worse than owning a smaller piece of something successful.

I could probably write another page of questions, but these are the three I'm struggling with the most:

  • How do you know when someone is worth bringing in as a true partner rather than just an advisor or consultant?
  • How do you determine a fair equity split when the product is already built but still early?
  • If your existing network doesn't contain the people you need, where do you actually go looking for them?
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u/PleasantLow670 — 20 days ago

Top 10 Lottery Formats by Simulated Win Rate (6,476 Plays Across 150 Days)

I thought some people here might find this interesting.

Over the last 150 days I've been collecting data from thousands of lottery simulations and finally decided to look at which lottery formats produced the highest win rates. Some of the results genuinely surprised me...

Obviously this doesn't mean these lotteries are "easier" to beat or that future results will be similar. These are simply the observed results from the simulation dataset.

Top 10 by Win Rate:

  1. 🇨🇿 Eurojackpot - 30.04% (67 wins / 223 plays)
  2. 🇧🇲 Lucky Pick - 28.33% (83 wins / 293 plays)
  3. 🇻🇮 Super Lotto - 24.32% (36 wins / 148 plays)
  4. 🇧🇧 Mega 6 - 17.76% (38 wins / 214 plays)
  5. 🇱🇺 High 5 - 17.60% (41 wins / 233 plays)
  6. 🇨🇭 Swiss Lotto - 16.85% (30 wins / 178 plays)
  7. 🇫🇷 EuroDreams - 14.55% (24 wins / 165 plays)
  8. 🇬🇷 Lotto - 13.58% (33 wins / 243 plays)
  9. 🇻🇨 Lotto - 12.92% (27 wins / 209 plays)
  10. 🇵🇱 Lotto - 12.58% (41 wins / 326 plays)

A few surprises:

• Eurojackpot finished far above the rest of the field.
• Lucky Pick generated the highest total number of wins.
• Some well-known formats such as Powerball (11.20%) and Mega Sena (10.53%) landed close to the middle of the pack.
• Several lotteries showed very low win frequencies despite substantial sample sizes.

I'm curious: If you regularly play lottery games, which format has felt the luckiest for you over time?

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u/PleasantLow670 — 20 days ago
▲ 8 r/cogsci

Can the mere possibility of a positive outcome create a feeling of luck?

A discussion here a few days ago about the feeling of being "lucky" led me to a related question that I haven't been able to stop thinking about.

Most discussions of luck seem to focus on outcomes. Something happens, and afterward we decide whether we were lucky or unlucky. But I'm wondering whether part of the feeling of luck exists before any outcome is known.

Consider a simple thought experiment.

At time T1, a person can either buy a lottery ticket or not buy one.

At time T2, the drawing takes place.

Between T1 and T2, nothing has happened yet. No win, no loss, no outcome.

Yet many people seem to experience a psychological difference during that period.

The person holding the ticket has access to a possible future in which something highly positive happens. The person without the ticket does not.

What's interesting to me is that people often describe themselves as feeling "luckier" during this period, even though the probability of winning has not changed and no outcome has occurred.

The effect seems even stronger when the potential reward is extremely large. A ticket with a possible $10 reward feels very different from one with a possible $100 million reward, despite both being unresolved possibilities.

Things become even stranger when another person enters the picture. Imagine that I choose not to buy a ticket, but my friend buys one using a number combination that I suggested.

If that combination later wins, many people would experience intense regret despite never participating in the lottery at all. If it loses, they may feel relief.

In both cases, the emotional response seems to depend not only on what happened, but also on an imagined alternative reality.

This makes me wonder whether subjective luck is partly a function of: outcomes, expectations, counterfactual thinking, perceived opportunity, and access to desirable possible futures.

Is there cognitive science research that looks at luck as a prospective experience rather than only a retrospective judgment?

More generally, do we know how people psychologically represent unrealized possibilities before outcomes occur?

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u/PleasantLow670 — 23 days ago
▲ 16 r/cogsci

Why does the feeling of being lucky seem so weakly connected to actual life circumstances?

Over the last few months I've read hundreds of Reddit comments where people were asked whether they consider themselves lucky.

What surprised me is that people often describe very similar lives but reach completely opposite conclusions.

For example: "I have food, shelter, good health, a family that loves me. I'm incredibly lucky" or "No. Everything I have came from hard work. Luck had nothing to do with it".

Some focus on surviving hardships and therefore feel lucky. Others focus on opportunities they never received and therefore feel unlucky.

This made me wonder: Do people actually evaluate luck?

Or are they evaluating something else entirely ... gratitude, perceived control, optimism, resilience, life satisfaction, attribution style, etc.?

Is there any cognitive science research on how people construct the feeling of being "lucky"? Because from what I've observed, the feeling of luck seems only loosely connected to the events people describe.

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u/PleasantLow670 — 26 days ago
▲ 54 r/tifu

TIFU by almost filling my windshield washer reservoir with antifreeze

This happened last winter.

For context, I'm not really a "car guy". I've owned a car for a few years, I drive when I need to, but I don't spend my weekends discussing engines, fluids, horsepower, or whatever else normal car enthusiasts enjoy. To me, a car is basically a large appliance that occasionally asks for money.

One cold winter day I ran out of windshield washer fluid. The roads were dirty, visibility was getting worse, and I decided I needed to solve the problem immediately.

I pulled into a gas station and walked over to a display full of colorful containers.

I spotted a blue one. It said "-35°C" on the label.

Perfect. Blue liquid. Winter temperature rating. Exactly what I needed.

Without reading anything else, I grabbed it, paid at the register, and confidently walked back toward my car.

My plan was simple: open the hood, pour it in, continue my journey like a responsible adult.

As I approached the car, one of the station employees noticed me carrying the container and started jogging toward me.

"Need help filling up your washer fluid?" he asked.

Before he reached me, another employee shouted from across the station:

"ARE YOU AN IDIOT? THAT'S ANTIFREEZE!"

Everything stopped. The employee froze. I froze.

For a brief moment I considered pretending I knew exactly what I was doing.

So that's exactly what I did.

I calmly walked around the car, opened the trunk, carefully placed the antifreeze inside as if that had been my plan all along, nodded respectfully, got into the driver's seat, and left.

Only later did I stop and actually read what antifreeze is and what could have happened if I had poured it into the windshield washer system.

The best part?

I later discovered that the antifreeze wasn't even compatible with my car model.

So apparently I had accidentally purchased the wrong fluid for the wrong system. So ... I'm still having it in my trunk.

To this day I'm still not entirely certain that I haven't done this before when nobody was around to stop me.

TL;DR: Ran out of windshield washer fluid, bought blue antifreeze because it looked right, nearly poured it into the wrong system until a gas station employee publicly saved me from myself.

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u/PleasantLow670 — 29 days ago
▲ 24 r/ChatGPT

ChatGPT didn't build my app. But I probably wouldn't have built it without ChatGPT.

I spent a few months building and launching a mobile app with ChatGPT as my primary technical collaborator. Not "generate a logo" or "write a tweet". I mean actual product development: Flutter code, Firebase architecture, database design, bug fixing, App Store submission, Google Play release, website creation, analytics, experiment design, content creation.

The app explores luck, probability, behavioral patterns, and real-world experiments. What's interesting isn't the app itself. It's that before this project I had never shipped a mobile application.

ChatGPT didn't magically build it for me. I still had to learn, debug, make decisions, and spend hundreds of hours implementing things. But it dramatically lowered the barrier between "I have an idea" and "I can actually build this." My biggest surprise wasn't coding. It was having a patient technical partner available 24/7 that could explain the same concept 20 different ways without getting frustrated.

Curious how many people here have actually shipped a real product with ChatGPT involved.

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u/PleasantLow670 — 1 month ago

Good luck is usually invisible

People notice bad luck immediately: a missed flight, a broken phone, a canceled event.

But good luck often goes completely unnoticed because it feels normal. The flight that wasn't delayed. The illness you never caught. The accident you narrowly avoided. The stranger who gave useful advice. The opportunity that appeared at the right time.

I think most people spend far more time noticing bad luck than recognizing good luck, even though both affect their lives every day.

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u/PleasantLow670 — 1 month ago

Does anyone else feel like some periods of life are just… statistically weird?

I’ve noticed there are stretches of time where tiny things keep lining up in strange ways. Random conversations happen at exactly the right moment. You think about someone and they suddenly message you. Small decisions unexpectedly work out better than they normally should. Even your timing feels different somehow. And then there are other periods where everything feels slightly “off.” Nothing catastrophic happens, but everything feels heavier, mistimed, delayed, or disconnected.

What’s interesting is that objectively the world probably hasn’t changed much at all. But your interaction with randomness somehow feels completely different depending on the period. I started paying attention to this after noticing some oddly specific coincidences over the last couple of years, and now I can’t tell whether humans are just extremely good at pattern recognition or whether our mental state genuinely changes how we move through situations.

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u/PleasantLow670 — 1 month ago

Can people feel “lucky” without actually risking money?

Can people emotionally experience “luck” without actually risking money?

That’s the question behind a small experiment I’ve been building recently.

The idea is simple: participants choose numbers and follow real lottery outcomes over time without spending their own money. The project tracks things like emotional reactions, streak perception, timing behavior, routines, optimism, “almost win” effects, and how people interpret randomness over long periods.

What interests me is that humans seem to naturally build narratives, attachment, and behavioral patterns around uncertainty even when there’s no direct financial risk involved.

At some point it starts feeling less like a lottery experiment and more like a psychology experiment around randomness itself.

Curious whether anyone here thinks the emotional side of lottery participation exists independently from the actual money involved.

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u/PleasantLow670 — 2 months ago

Why is it easier to act when you feel like you’re moving in the “right direction”?

Lately I’ve been wondering if a lot of motivation actually comes from feeling like your effort means something. Not guaranteed success. Not certainty. Just some small sense that continuing might eventually matter.

I noticed that when I treat life like a pure optimization problem, I often freeze. I overthink everything, try to control outcomes, wait until I’m “sure.” But when there’s even a small feeling that maybe I’m moving in a meaningful direction, action becomes easier.

Almost like the brain needs some form of emotional confirmation before it fully commits energy. What’s strange is that I don’t think people are always looking for certainty as much as they’re looking for permission to keep moving despite uncertainty.

Even tiny signals lije a good conversation or a small win at the right moment can change behavior. Not because they prove anything objectively, but because they reduce friction enough to continue. Now I’m wondering whether a lot of “motivation” is actually just the feeling that your actions are connected to something larger than immediate results.

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u/PleasantLow670 — 2 months ago

LPT: Don’t trust “this feels like the right moment” until you’ve tracked it a few times.

That “this feels right” moment is powerful but also unreliable.

Start writing down those moments before acting on them. After a few weeks, check what actually happened. You’ll usually find that some patterns are real but most are just your brain connecting dots after the fact. Tracking it once or twice isn’t enough but over time, it becomes surprisingly clear.

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u/PleasantLow670 — 2 months ago