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percentage uncertainties/percentage error


LMaxwell

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Rest assure. It is perfectly fine to have percentage error>percentage uncertainty. All that means is that the experiment probably more accurate than precise. I think you already answered your own question :lol:

Accuracy is how close your experimental value is to your to the literature value, which is measured by %error.

Uncertainty is the equal chance of measuring something too high or too low, which is measured by uncertainty/ %unc.

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Rest assure. It is perfectly fine to have percentage error>percentage uncertainty. All that means is that the experiment probably more accurate than precise. I think you already answered your own question :lol:

Accuracy is how close your experimental value is to your to the literature value, which is measured by %error.

Uncertainty is the equal chance of measuring something too high or too low, which is measure by uncertainty/ %unc.

But it still means that my experiment was inaccurate right? How would I explain this?

Edited by brofessional
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In your typical chemistry experiment, a percentage error of 3% is rather small actually, so I wouldn't say it is inaccurate. Percentage error is due to systematic errors within the experiment, which are inherent problems with procedure. Systematic errors cannot be reduced through repeating trials, unlike random error, which is used to explain uncertainty.

As for explaining it, that all depends on the experiment. Where do you think the procedure may have led to inaccurate results? Remember, a better designed procedure will reduce systematic error.

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That's wrong. Random error has nothing to do with your accuracy. Percentage error deals with how close you are to the literature value. The random error only affects the range of your experimental value; it has no influence in the percentage error calculation.

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bro,

when % unc > % error, random errors > systematic errors, and you must focus on improving the precision.

when % error > % unc, systematic errors > random errors, and you must focus on improving the accuracy.

I rarely get my % error low though, have you double-checked your calculations? one day I was very happy to have a 5% error but it turned out I made a calculation mistake and my error was actually 20%ish.

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