love it! gonna use this instead of calculating my own extremes now
Show HN: Unsure Calculator – back-of-a-napkin probabilistic calculator
91–100 of 170 posts
Re: Show HN: Unsure Calculator – back-of-a-napkin probabilistic calculator
#92Re: Show HN: Unsure Calculator – back-of-a-napkin probabilistic calculator
#93Earlier quoted context omitted.
It is producing a useful number. As more truly independent terms are added, error grows with the square root while the point estimation grows linearly. In the aggregate, the error makes up less of the point estimation. This is the reason Fermi estimation works. You can test people on it, and almost universally they get more accurate with this method. If you got less certain of the result in the example, that's probab…
> People are default overconfident with their estimated error bars. You say this but yet roughly in a top level comment mentions people keep their error bars too close.
They are meaning the same thing. The original comment pointed out that people’s qualitative description and mental model of the 95% interval means they are overconfident… they think 95 means ‘pretty sure I’m right’ rather than ‘it would be surprising to be wrong’
Re: Show HN: Unsure Calculator – back-of-a-napkin probabilistic calculator
#94Interval/affine arithmetic are alternatives which do not make use of probabilities for this these kinds of calculations.
https://en.wikipedia.org/wiki/Interval_arithmetic
I think arbitrary distribution choice is dangerous. You're bound to end up using lots of quantities that are integers, or positive only (for example). "Confidence" will be very difficult to interpret.
Does it support constraints on solutions? E.g. A = 3~10, B = 4 - A, B > 0
Re: Show HN: Unsure Calculator – back-of-a-napkin probabilistic calculator
#95I love it! Now I need it in every calculator
Re: Show HN: Unsure Calculator – back-of-a-napkin probabilistic calculator
#96I like this! In the grand HN tradition of being triggered by a word in the post and going off on a not-quite-but-basically-totally-tangential rant: There’s (at least) three areas here that are footguns with these kinds of calculations: 1) 95% is usually a lot wider than people think - people take 95% as “I’m pretty sure it’s this,” whereas it’s really closer to “it’d be really surprising if it were not this” - by and…
I did a project with non-technical stakeholders modeling likely completion dates for a big GANTT chart. Business stakeholders wanted probabilistic task completion times because some of the tasks were new and impractical to quantify with fixed times. Stakeholders really liked specifying work times as t_i ~ PERT(min, mode, max) because it mimics their thinking and handles typical real-world asymmetrical distributions.…
arguably this is how it should always be done, fixed durations for any tasks are little more than wishful thinking.
Re: Show HN: Unsure Calculator – back-of-a-napkin probabilistic calculator
#97Love it! I too have been toying with reasoning about uncertainty. I took a much less creative approach though and just ran a bunch of geometric brownian motion simulations for my personal finances [0]. My approach has some similarity to yours, though much less general. It displays the (un)certainty over time (using percentile curves), which was my main interest. Also, man, the UI, presentation, explanations: you did a great job, pretty inspiring.
[0] https://dmos62.github.io/personal-financial-growth-simulator...
Re: Show HN: Unsure Calculator – back-of-a-napkin probabilistic calculator
#98The histogram is great, nice work;
I want to ask about adjacent projects - user interface libraries that provide input elements for providing ranges and approximate values. I'm starting my search around https://www.inkandswitch.com/ and https://malleable.systems/catalog/ but I think our collective memory has seen more examples.
Re: Show HN: Unsure Calculator – back-of-a-napkin probabilistic calculator
#99Would be nice to retransform the output into an interval / gaussian distribution Note: If you're curious why there is a negative number (-5) in the histogram, that's just an inevitable downside of the simplicity of the Unsure Calculator. Without further knowledge, the calculator cannot know that a negative number is impossible Drake Equation or equation multiplying probabilities can also be seen in log space, where t…
The default example `100 / 4~6` gives the output `17~25`
Amazing, thank you !
Re: Show HN: Unsure Calculator – back-of-a-napkin probabilistic calculator
#100I think the SWI Prolog clpBNR package is the most complete interval arithmetic system. It also supports arbitrary constraints.