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by devereaux
2710 days ago
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Assuming we are talking about software, error between measurements is a direct function of the device you use to measure, which is itself close to perfect Even if we go to the example you give, the measurement should be done n times, each reporting the exact result found like 51.0 51.9 51.95 etc. Even if the decimals are outside the smallest interval of your ruler: take enough of them and you can get closer to the actual length which may be 51.55345 and that you would never have been able to measure anyway without a caliper The best thing is you can even do that by resampling old measurements (a process called bootstrapping) So yes, if you remove the tenth of millimeters, you lose information. What's wrong is not the number, but that custom makes people think 51.0 means 51.0 +- 0.01 or anything else while it was never said like this. |
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Why you do multiple measurements is because as humans we are imprecise. Any engineer, wood worker, whatever knows the saying "measure twice, cut once". In your example, the thing you are measuring could well be exactly 52.0000...cm.
If you don't believe me I seriously want you to ask ANY physicist. They can even be an undergraduate (assuming they aren't a freshman) and they should know this. We even use this to figure out what we should spend money on. We can process these errors and determine which measuring device needs more certainty and buy that new device.
This is WHY we have very precise devices. With your method, we could theoretically get measurements to nanometer levels. I can tell you, I would much rather spend 15 minutes making a hundred measurements than spending thousands of dollars on a laser and equipment needed to make precise measurements down to the nm level.
To sum up:
> take enough of them and you can get closer to the actual length which may be 51.55345
NO! This is just dead wrong. It'd be right if you said 51 or 52.
> that you would never have been able to measure anyway without a caliper
No! This is why we have calipers!
> if you remove the tenth of millimeters, you lose information.
Not if you didn't have that information in the first place.
>What's wrong is not the number
Yes it is.
I can only assume: 1) You are trolling, 2) You are really thick headed, and/or 3) You've never taken a physics class. I'm not saying anything here that isn't easily verifiable. I have others backing me up. So if you have no interest in learning, then there is no point for me to continue.