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Explain why is a highly precise measurement doesn't not always mean a highly accurate one?
Wiki User
∙ 7y ago
Accurate means how close the measured value is to the real, actual value. Precise means how reproducible the measurement is. So, if the real value is 1.00, and you measure it to be 0.785, and every time you measure it, it comes out the same (0.785), then the measurement is VERY precise, but not very accurate.
Wiki User
∙ 7y ago
Wiki User
∙ 7y agoThese are different statistical parameters; accuracy is the deviation from the supposed true value and precision is the scatter of the experimental results. So measurements can be precise but erroneous.
Wiki User
∙ 7y agoIf you do an experiment where the result is expected to be 5. Suppose you carry out the experiment four times and get 5.08, 5.09, 5.11 and 5.12 (mean = 5.1) each time. Suppose another person gets the results 4.8, 4.9, 5.1 and 5.3 (mean (5.025).
Then your result is very precise but the other person is more accurate. The other person's mean result is closer to the expected result than yours is.
Precision is a measure of how closely the measurements match one another even if they are way off from the "true value" whereas accuracy is a measure of how close they are to the true value even if they are not all similar.
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Are precise measurements always accurate?
No. A broken clock gives a very precise time, but most of the time it is wrong.
Most stars have such small parallax shifts that accurate measurement is always possible?
On the contrary, if the parallax angle is too small, it can't be measured accurately.
Is it possible to calibrate a ruler so accurately that measuring uncertainty is eliminated?
Mini RulerHeh, maybe, but you'd need an extremely strong microscope to read it, along with some that could print numbers that small. Hope that was helpful.Second opinion: The answer is no. There is always some level of uncertainty in any measurement. Even if you could measure down to the atomic scale, there are still sources of error in the measurement.The other issue is the difference between precision and accuracy. Precision is the ability for you to make the same measurement every time you make it. So for example, if you are measuring the length of an object, assuming that the object does not change length, you measure the same number every time.Accuracy is the degree to which your measurement reflect the true value.So lets say you have an object that is 12 inches long. That is it's true value. You grab a ruler and measure it to be 11.96 inches long. There is 0.04 inches of error in your first measurement. You can repeat this measurement and you will not get the same thing every time. So your second measurement results in 11.92 inches, third is 12.03 inches... all very close to the true value, but not EXACTLY 12. If a great number of measurements average out to be 12 inches, then you are using a pretty ACCURATE measuring device. What would happen if you had a device that measured 11 inches EVERY TIME... that would be a case of having a very PRECISE measurement, but not very accurate.The goal of any measuring device is to be both precise AND accurate... that would be like having a device measure your 12 inch long object to be 11.98,12.02,11.99, etc. Every measurement you make is very close to each other AND to the true value of the object you are measuring.How do you know the true value?? Ah ha...now you are thinking. You gather the most precise and accurate measuring devices in the world and you take ALOT of measurements. You compare your results to the results from other labs around the world and analyze the data to determine how accurate and precise you can make a measurement. These are usually done to a level of accuracy and precision far beyond anyone's need for any better... in most cases.
What two things does a measurement statement always contain?
useful
In order to make sense a measurement always have a what and a what?
-- number -- unit
Is less precise instrument always more accurate?
No. Accurate relates to how close the actual measurement the instrument measures. Precise relates to how much detail the instrument gives when measuring. They are independent to each other: An measurement can be precise and accurate (eg the value of π is 3.141592654) An measurement can be precise and inaccurate (eg the value of π is 1.733677432) An measurement can be less precise and accurate (eg the value of π is 3.14) An measurement can be less precise and inaccurate (eg the value of π is 1.73).
Are precise measurements always accurate?
No. A broken clock gives a very precise time, but most of the time it is wrong.
Why does universal indicator not always give an accurate result?
Universal indicator is just that - an indicator. It is not intended as an accurate measurement system.
What is Limit of precision?
The precision of something just means that the result can be repeated again and again. Everytime you repeat an experiment, you will get the same result. But that doesn't necessarily mean that the results are accurate! Your measurments, results, whatever can be very precise, but completely inaccurate. Accuracy is how close something is to the true value. For example, say I have a ruler. I have used this ruler to measure my table 10 times. Every time I measure the table, I get a measurement of 10ft. My measurement is very precise. However, what I don't know is that there is a fault with my ruler. The inches on my ruler are not true inches. Each inch may actually be only 1/9th of an inch. Or all the inches on my ruler may not even be the same. So while my measurements I took with my ruler 10 times are precise, they are not accurate because there is fault with my ruler. Something can be precise, but not necessarily accurate! I would say that this is the biggest limitation of precision. A precise measurement is not always a reliable one!
Is millimeter precise than decimeter?
Millimetres would allow for more precision than decimetre. If you can measure a smaller quantity, this always allows you to be more precise and accurate.
Explain why long term forecast aren't always accurate?
no one can tell
Explain why long term forecasts aren't always accurate?
no one can tell
When is a measurment accurate?
Never: A measurement made is always an approximation. We can get very close to being accurate with our measurements, but never fully 100% accurate. This is not the fault of the person measuring, or what tool they are using to measure with, but it is a natural law that we (anyone, even superior aliens to humans) cannot ever fully make an absolutely accurate measurement.
Why is significant figures important is measurement?
Significant figures are important in measurement because they determine how accurate a scientific claim can be. There always has to be a small amount of uncertainty in an answer, because no measurement or calculation is ever 100% absolute.
What is a measurment closee to the true size?
Accuracy
Is the border of Alaska precise?
With modern technology like GPS it is precise and accurate, but because these tools of modern surverying were not always available, there are surely border markers in remote areas that display gross errors.
What is the differnace between precision and accuray?
Precisoin is how consistent you are to hitting a target, for instance if you were shooting free throws, and you always hit the front of the rim that would be precise but NOT accurate. And accuracy is both precision and accuracy. So instead of being precise by hitting the front of the rim, you would make the shot by being accurate.
