# 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:

$Err_{abs}=∣x_{exact}−x∣$

### Relative Error

The relative error is given by $Err_{rel}=∣x_{exact}∣∣x_{exact}−x∣ $