Error

Three Sources of Error

True error: Mistakes made in the measurement.

• Ex: Experimenter reading a scale on a measurement incorrectly.

Random error: Result from limitations in the precision of the measurements.

Systematic error: Result from some bias in the way that the quantity is being measured.

• Ex: Measuring a current with a ammeter that is not properly calibrated.

Accuracy vs Precision

Accuracy: How close the measurement is to some quantity.

Precision: Measure of how close repeated measurements are to one another.

CS370

Absolute Error

When we obtain a computed result x of some calculation and we wish to discuss its relationship with the correct mathematical result $x_{exact}$, we can measure either the absolute error:

$Er{r}_{abs}=|x_{exact}-x|$

Relative Error

The relative error is given by $Er{r}_{rel}=\frac{|x_{exact}-x|}{|x_{exact}|}$