3 ms·
>how can your accuracy on the error bars themselves be 4 significant figures They aren't, but that's still the number you got. Chopping off the digits means yo
by Aerroon 6y ago
>how can your accuracy on the error bars themselves be 4 significant figures
They aren't, but that's still the number you got. Chopping off the digits means you're slightly changing the result. It's like Tic Tac and their "0g of sugar" label, despite being 90% sugar.
- theptip 6y agoIt’s probably not the number they got though; the STDDEV calculation or whatever error measure you choose will usually give you lots more decimal places. The decision was taken to round to 4 significant figures. If you got 10 decimal places in your calculation, it would obviously be nonsense to give all of them.
- patall 6y agoBut the "0g of sugar" in TicTac is something totally different. The difference between 25.68 and 26 is 2% of the total number (while the error of 40 is almost 160%). The difference between 0.01 and 0 is 100%.
- Erlich_Bachman 6y agoDid you just divide by zero?
- WJW 6y agoHe divided by 0.1, otherwise he would never have gotten to 100%.
- Aerroon 6y agoMy point is that it allows these kinds of things to happen. What's the point in making the number less accurate? In probability the difference between 0.999 vs 1.0 is enormous and these kinds of things can happen when you just floor numbers.
- andreareina 6y agoI think the point is that given the size of the error bars, that much precision is not an accurate representation of the confidence we should have in the result. 25.68% might be the observed change, but it's not one we should have much confidence of being accurate, not to four significant figures. Glibly put, it's false precision. No-one I've seen arguing for fewer significant digits says that a probability of 0.999 should be rounded to 1. Nor do they say it's ok to round 0.5 to 0.
- gliptic 6y agoThere's no false precision. There's a whopping +/- 40% error bar! What can be said is that 26% is at least less precise on average. You've added a completely arbitrary 0.32 because of some obsession with decimals.
- andreareina 6y agoI think we're in agreement that the 0.32 is false precision?
- gliptic 6y agoNo, because there's an error bar. Why is 0.32 the false precision and not some other random number.
- sfkdjf9j3j 6y agoI think if you're doing this level of nit-picking, it's far more likely that somewhere along the line a scientist used a 32 bit floating point in their analysis and blew the precision out of the water before the number even got to you.