Uncertainty and Bias

Measurement Uncertainty (precision) - an estimate of likely limits to the experimental error

• tend to be random in nature
• a measurement is useless unless there is some way of estimating the associated uncertainty
• good analyses should include uncertainty estimates

Accuracy (bias) - difference between your measurement (mean value) and the truth.

• good analyses should include bias estimates as well.

Important: accuracy is not the same as uncertainty!

• Can have an accurate measurement with a large uncertainty.