# calculating absolute and percentage error in temperature measurement?

Not sure how to do this, anyone got any ideas?

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Absolute Error is when you subtract the accepted value from your measured value…

Absolute Error = Measured Value - Accepted Value

* A positive answer means you are over the accepted value.

* A negative answer means you are under the accepted value

Percentage Error is the most common way of measuring an error, and often the most easy to understand.

Percentage Error = Absolute Error / Accepted Value

So, if you measured a pencil to be 102mm long, and an independent lab with high tech equipment measured it as 104mm, the percentage error is…

Percentage Error = (102mm - 104mm) / (104mm) = -0.02

Which means you got a -2% error. The minus sign just means that you were under the accepted value.

In high school labs, don’t be surprised if you obtain errors of 25%. The important part is, can you explain your errors!

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• Percent Error Calculation

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• Bert is correct except for one point:

Temperature in ºF or ºC has an arbitrary zero point, therefore percentage error is meaningless. If you really want percent, you have to convert temperatures to a true zero base, such as ºK or ºR.

One example will show this. If your thermometer has a 1º error, then for a 100º measurement, that is 1% error. For a measurement at 1º, that changes to a 100% error, and at 0º, an infinite percent error.

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