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A comment on A CO2 capture solvent with exceptionally low total costs of capture. Parent comment

Re:A CO2 capture solvent with exceptionally low total costs ... by phreeza on Sunday April 04, 2021 @02:22PM (#26691666)
In my experience, the obsession with correct significant figures is an american high school thing. Why should you deliberately have to choose a number that is not your best guess? Ideally you should include confidence bounds, but if you don't, it shouldn't imply that you are confident to that level.
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Re:A CO2 capture solvent with exceptionally low total costs ... by jfim on Sunday April 04, 2021 @03:20PM (#26692087)
Because it gives an idea of what range is expected for the actual price. If someone gets an estimate of "about fifty bucks" versus "about $51.04", their reaction to seeing a final price of say $62.17 would be different. The first one implies that it's a rough estimate, while the second one doesn't.
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Re:A CO2 capture solvent with exceptionally low total costs ... by phreeza on Sunday April 04, 2021 @03:34PM (#26692181)
"About" is doing a lot of work, too, no?
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Re:A CO2 capture solvent with exceptionally low total costs ... by throwawayfire on Sunday April 04, 2021 @04:13PM (#26692483)
If someone said "about fifty bucks" and it turns out to be $62.17, I'd immediately understand them to be scamming me.
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Re:A CO2 capture solvent with exceptionally low total costs ... by jfim on Sunday April 04, 2021 @04:41PM (#26692654)
Really depends on what the context is. Maybe for a taxi ride when negotiating a price ahead of time, but pointing at an object, asking for its price, getting an estimate that's off, then getting the actual price before the transaction is completed doesn't feel like a scam.
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Re:A CO2 capture solvent with exceptionally low total costs ... by Scipio_Afri on Sunday April 04, 2021 @07:07PM (#26693621)
Please price estimates for car repairs in dollars and cents and state it's only an estimate all the time.. with variations possible depending on what's discovered that might have been missed it that particular context.
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Re:A CO2 capture solvent with exceptionally low total costs ... by nullc on Sunday April 04, 2021 @03:14PM (#26692037)
Yep. The weird thing is that their sigfig rules of thumb aren't particularly accurate and after any non-trivial operations (or more than a few operations) just give wrong results.

Tracking precision through calculations requires interval arithmetic, which is a pretty big PITA and not frequently used.

I think the sig figs cult comes out of mistaking a simplified lesson on precision for a useful practice.

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Re:A CO2 capture solvent with exceptionally low total costs ... by LasEspuelas on Sunday April 04, 2021 @06:13PM (#26693292)
Not sure exactly what you mean. It is well known that you should keep additional digits throughout the calculation and then drop non-significant ones for final results.
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Re:A CO2 capture solvent with exceptionally low total costs ... by nullc on Monday April 05, 2021 @12:44AM (#26695432)
The number of digits out is only a simple function of the digits in if you're doing fairly trivial calculations.

Checkout https://en.wikipedia.org/wiki/Interval_arithmetic for what it takes to monitor precision through complex calculations (in particular, see the bits about using the taylor expansions of non-trivial functions).

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Re:A CO2 capture solvent with exceptionally low total costs ... by Gibbon1 on Sunday April 04, 2021 @02:43PM (#26691800)
When I was getting my engineering degree too many significant figures would earn you -2 pts.
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Re:A CO2 capture solvent with exceptionally low total costs ... by lb1lf on Sunday April 04, 2021 @04:24PM (#26692562)
Measure with a micrometer.

Mark with a chalk.

Cut with an axe.

(Apparent practice at a workshop I used to frequent.)

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Re:A CO2 capture solvent with exceptionally low total costs ... by Gibbon1 on Sunday April 04, 2021 @04:47PM (#26692688)
Old crusty semi-retired engineer I knew said when he was young he liked designing things to close tolerances. But once he was old he found more pleasure in designing things that worked with really shitty tolerances.
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Re:A CO2 capture solvent with exceptionally low total costs ... by lb1lf on Sunday April 04, 2021 @05:06PM (#26692839)
-I had a colleague once, fresh out of mechanical engineering at the local univerity college, who as his first project did a locking pawl for a winch drum.

Tolerance? H7.

The fitters threw a fit trying to make that happen.

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Re:A CO2 capture solvent with exceptionally low total costs ... by throwaway0a5e on Sunday April 04, 2021 @08:55PM (#26694293)
Clearly he wasn't working in any sort of mechanical capacity while getting that community college degree.
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Re:A CO2 capture solvent with exceptionally low total costs ... by adrianmonk on Sunday April 04, 2021 @02:37PM (#26691765)
That's definitely where I learned that it was expected.

I look at it as one of many possible conventions for communicating precision. For what it is, it works well. But it's not universal, and people who do and don't use it should both keep in mind that the other group exists.

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Re:A CO2 capture solvent with exceptionally low total costs ... by kortilla on Sunday April 04, 2021 @05:20PM (#26692952)
It hints that someone doesn’t understand these confidence values at all.

Why $47.10 and not $47.1032471?

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