How to Calculate Percent Error in Measurements

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Discussion Overview

The discussion centers around the calculation of percent error in measurements, particularly using a meter stick for measuring distances in centimeters. Participants explore the definitions and calculations involved in determining percent error, including concepts of absolute and relative error.

Discussion Character

  • Technical explanation, Mathematical reasoning, Conceptual clarification

Main Points Raised

  • One participant asks how to calculate percent error when measuring a distance with a meter stick, questioning its accuracy to the millimeter.
  • Another participant suggests that using millimeter marks implies a maximum error of 1 mm.
  • A different participant clarifies that the maximum error represents a tolerance interval and not a percentage, proposing a calculation for percent error based on a specific measurement of 20.2 mm.
  • One participant reiterates the calculation of relative error as the absolute error divided by the actual measurement, defining absolute error as the smallest division of the meter stick (1 mm).

Areas of Agreement / Disagreement

Participants present various interpretations and calculations regarding percent error, with no consensus reached on a definitive method or agreement on the calculations proposed.

Contextual Notes

Some participants express uncertainty regarding the definitions of absolute and relative error, and there are unresolved aspects related to the application of these concepts in specific measurement scenarios.

Joza
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How does one calculate percent error in measurements?

In attempting to measure a distance of some centimeters with a meter stick, how could I estimate it?

Isn't a meter stick accurate to the millimeter?
 
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Well, if you use the millimeter marks to measure that distance, the maximum error that you could have would be 1 mm.
 
Manchot said:
Well, if you use the millimeter marks to measure that distance, the maximum error that you could have would be 1 mm.

That's tolerance interval. It's not a percentage. I think, but don't know, but if you measure 20.2 milimeters on your measuring stick, and the most you can be off by is 1 mm than your percent error is that 1mm over 20.2 gives you percent error of.049, or 5%.
 
Joza said:
How does one calculate percent error in measurements?

In attempting to measure a distance of some centimeters with a meter stick, how could I estimate it?

Isn't a meter stick accurate to the millimeter?

MagikRevolver is correct.

The relative error is simply the absolute error divided by the actual measurement (the value of the thing you are measuring).

Absolute error is the amount of physical error in a measurement. The absolute error in your case is the smallest division of the meter stick, or 1 mm.

Hence, the relative error in this case is 1 mm/x mm where x is your actual measurement.
 

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