4 ms·

But the thing being concluded is that it's not very bumpy, and for that conclusion to hold water the data needs to be both accurate and precise within some very

by hansvm 4y ago

But the thing being concluded is that it's not very bumpy, and for that conclusion to hold water the data needs to be both accurate and precise within some very small bound. Spitting out precise measures of electron bumpiness isn't very hard without that accuracy. Right this second I used the "gut feeling" measurement device to conclude that the electron is round within 1024 bits of precision, and yet the authors have a publication and I don't. Is their conclusion over-blown?

AnimalMuppet 4y ago
I don't think so. They're not measuring the radius to precision 10^-31 cm. They're measuring the differences in radius against zero, and they know the value of zero to infinite precision.
- hansvm 4y ago
  Sure, but it's precisely that difference which they claim to be measuring. Why does it matter that they don't also know some other value (the radius) to high accuracy? It's kind of like how a balance can measure the difference in force to high accuracy (and precision), but that doesn't mean we know anywhere near that much about the masses on the balance, and...it doesn't have to; you can just state that you know some delta accurately and not have to explain why that means some auxiliary measurement is probably precise.
moron4hire 4y ago
Say I devised a test of the smoothness of steel ball bearings. Maybe it'd be something like rolling the bearing around on a soft substrate and then checking the substrate for scratches. That test would be precise (I'd know the maximum bound on the size of imperfections in the bearing) but not accurate (it wouldn't tell me anything about the absolute radius of the bearing or the location of the imperfections). The point is, with the information given, we haven't been told anything about the accuracy of the test. Maybe it is. Maybe it isn't. That's just blank information. We've only been told the precision.

by hansvm 4y ago

AnimalMuppet 4y ago

I don't think so. They're not measuring the radius to precision 10^-31 cm. They're measuring the differences in radius against zero, and they know the value of zero to infinite precision.

hansvm 4y ago
Sure, but it's precisely that difference which they claim to be measuring. Why does it matter that they don't also know some other value (the radius) to high accuracy? It's kind of like how a balance can measure the difference in force to high accuracy (and precision), but that doesn't mean we know anywhere near that much about the masses on the balance, and...it doesn't have to; you can just state that you know some delta accurately and not have to explain why that means some auxiliary measurement is probably precise.

moron4hire 4y ago

Say I devised a test of the smoothness of steel ball bearings. Maybe it'd be something like rolling the bearing around on a soft substrate and then checking the substrate for scratches. That test would be precise (I'd know the maximum bound on the size of imperfections in the bearing) but not accurate (it wouldn't tell me anything about the absolute radius of the bearing or the location of the imperfections). The point is, with the information given, we haven't been told anything about the accuracy of the test. Maybe it is. Maybe it isn't. That's just blank information. We've only been told the precision.