So is it like plugging in a normal distribution into some arithmetic? Consider maybe 1 + 1 ~ +-2 like Q factor, if you know what I mean. That would help to filter out more probabilistic noise in using it to help reason with.
Show HN: Unsure Calculator – back-of-a-napkin probabilistic calculator
131–140 of 170 posts
Re: Show HN: Unsure Calculator – back-of-a-napkin probabilistic calculator
#132I 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…
Re: Show HN: Unsure Calculator – back-of-a-napkin probabilistic calculator
#133I 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…
Re: Show HN: Unsure Calculator – back-of-a-napkin probabilistic calculator
#134https://qalculate.github.io can do this also for as long as I've used it (only a couple years to be fair). I've got it on my phone, my laptop, even my server with apt install qalc. Super convenient, supports everything from unit conversion to uncertainty tracking The histogram is neat, I don't think qalc has that. On the other hand, it took 8 seconds to calculate the default (exceedingly trivial) example. Is that Jav…
Re: Show HN: Unsure Calculator – back-of-a-napkin probabilistic calculator
#135Earlier quoted context omitted.
The calculator in Emacs has support for what it is you request, which it calls "interval forms". Interval form arithmetic simply means executing the operations in parallel on both ends of the interval. It also has support for "error forms" which is close to what the calculator in OP uses. That takes a little more sophistication than just performing operations on the lower and upper number in parallel. In particular,…
Is it actually just doing it at both ends or something nore complex? Because for example if I did 7 - (-1~2)^2 the actual range would be 3-7 but just doing both ends of the interval would give 3-6 as the function is maximised inside the range.
Re: Show HN: Unsure Calculator – back-of-a-napkin probabilistic calculator
#136I 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…
Normal distributions are the maximum entropy distributions for a given mean and variance. Therefore, in accordance with the principle of maximum entropy, unless you have some reason to not pick a normal distribution (e.g. you know your values must be non-negative), you should be using a normal distribution.
...if the only things you know about an uncertain value are its expectation and variance, yes.
Often you know other things. Often you don't know expectation and variance with any certainty.
Re: Show HN: Unsure Calculator – back-of-a-napkin probabilistic calculator
#137I 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’ve just seen a lot of people pick up statistics for the first time and lose a finger. I love this. I've never though of statistics like a power tool or firearm, but the analogy fits really well.
Re: Show HN: Unsure Calculator – back-of-a-napkin probabilistic calculator
#138I actually stumbled upon this a while ago from social media and the web version has a somewhat annoying latency, so I wrote my own version in Python. It uses numpy so it's faster. https://gist.github.com/kccqzy/d3fa7cdb064e03b16acfbefb76645... Thank you filiph for this brilliant idea!
Nice! Are you using your python script often? The reason I'm asking: unsure also has a CLI version (which is leaps and bounds faster and in some ways easier to use) but I rarely find myself using it. (Nowadays, I use https://filiph.github.io/napkin/ , anyway, but it's still a web app rather than a CLI tool.)
Re: Show HN: Unsure Calculator – back-of-a-napkin probabilistic calculator
#139Earlier quoted context omitted.
I strongly agree with this, and particularly point 1. If you ask people to provide estimated ranges for answers that they are 90% confident in, people on average produce roughly 30% confidence intervals instead. Over 90% of people don't even get to 70% confidence intervals. You can test yourself at https://blog.codinghorror.com/how-good-an-estimator-are-you/ .
From link: > Heaviest blue whale ever recorded I don't think estimation errors regarding things outside of someone's area of familiarity say much. You could ask a much "easier"" question from the same topic area and still get terrible answers: "What percentage of blue whales are blue?" Or just "Are blue whales blue?" Estimating something often encountered but uncounted seems like a better test. Like how many cars pas…
For some of these, your answer could span orders of magnitude. E.g. my answer for the heaviest blue whale would probably be 5-500 tons because I don't have a good concept of things that weigh 500 tons. The important point is that I'm right around 9 times in 10, not that I had a precise estimate.
Re: Show HN: Unsure Calculator – back-of-a-napkin probabilistic calculator
#140I 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…
Normal distributions are the maximum entropy distributions for a given mean and variance. Therefore, in accordance with the principle of maximum entropy, unless you have some reason to not pick a normal distribution (e.g. you know your values must be non-negative), you should be using a normal distribution.