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# Maximum expected error

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1. Hi,

I have a question that i would like answered. Would be greatly appreciated Thanks.

What is the max expected error if a -100 to 300 degree C thermometer has a stated accuracy of + or -1.5% of the measurement range.

Also what would the maximum expected error be at 130 degree C.?
2. If you are saying that this error relates to the particular measurement range being used on the instrument, then the error is 1.5% of the upper value in this range. (With negative ranges taking the more negative value.)
So if you mean the maximum absolute error in a reading then it would be the error associated with the maximum value (positive or negative) that you can read with the instrument on a particular range setting.
In that case if the max value you can measure on a range is 300 deg C the error associated with that is ± 4.5 deg C which represents 1.5% of 300
For 130 degs it will depend on what scale range you measure that on.
If it was measured on, say, a 100 to 200 deg range setting, then the max error would be 3 deg C, being 1.5% of 200

Edit: It could also possibly mean 1.5% of the actual range. In that case it would be 1.5% of 100 as the range is 100 degs from 100 to 200.

Sorry I'm a bit vague.
It would help to have more information about the instrument and what you are measuring.
It's a bit difficult without seeing or using the instrument.
3. Hi Stonebridge,

Have for the reply, I have been informed that the Max expected error would be + or - 6 degree C.

Condidering the range -100 to 300, will be a total range of 400
+ or - 1.5% of 400 is + or -6 degree C.

Not sure about what the max expected error at 130 degree C for the same ranges.
4. (Original post by keroseneman)
Hi Stonebridge,

Have for the reply, I have been informed that the Max expected error would be + or - 6 degree C.

Condidering the range -100 to 300, will be a total range of 400
+ or - 1.5% of 400 is + or -6 degree C.

Not sure about what the max expected error at 130 degree C for the same ranges.
That makes sense. If there is just one range from -100 to 300 then you have a total of 400 and a % uncertainty of ±1.5% of 400 giving ±6 degs.

Regarding the value for 130 degs it looks to me as though the uncertainty is still ±6 degs as it seems to be saying that the uncertainty is 1.5% of the total 400 deg range.

Normally % uncertainties are related to the actual measurements, which would give 1.5% of 130 here. (±2 degs).
However, taking this literally would mean you have an error of zero for a reading of zero degrees. This doesn't make sense.
In which case I would stick to the original idea that the absolute error is always 1.5% of the range. Here ±6degs as discussed.

If this turns out not to be the case I would be interested in knowing exactly what they mean here for future reference.

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