Uncertainty

Uncertainty is the estimate of the range between the minimum and maximum. It represents the reliability of the measurement.

$\text{Absolute Uncertainty} = \frac{\text{maximum}-\text{minimum}}{2}$

then when writing the absolute uncertainty.

$\text{Mean Value } \pm \text{ Absolute Uncertainty}$

Error

Error is the difference between the measured value and expected value.

Random

Random errors refers to the random fluctuations of data. This can be because:

• Readability of instrument.
• Slightly changing any part of the environment between measurements.

Random errors can be reduced by averaging. A precise experiment has little random error.

Systematic

Systematic errors refers to the reproducible fluctuations of data. This can be because:

• An instrument being calibrated incorrectly.
• Zero error (when it does not show 0 when it should).
• The observer making small mistakes while making observations or measuring.

Systematic errors are hard to detect as they affect all of the measurements by the same amount. When you graph the data against the theoretical data, you can see that there is error.

Parallax Error