Uncertainty

Definition

Uncertainty quantifies the doubt about the result of a measurement. It defines the range within which the true value is expected to lie.

5 Must Know Facts For Your Next Test

1. Uncertainty is usually expressed with a plus-minus ($\pm$) notation.
2. Significant figures in a measurement affect its uncertainty.
3. The uncertainty in measurements can be due to systematic errors, random errors, or both.
4. When multiplying or dividing measurements, the relative uncertainties are added.
5. For addition and subtraction, absolute uncertainties are added.

Review Questions

• What does an uncertainty of $5 \pm 0.2$ units imply?
• How do significant figures influence uncertainty in measurements?
• What are the primary sources of uncertainty in measurements?

Related terms

Significant Figures: The digits in a measurement that carry meaning contributing to its precision.

Systematic Error: Consistent, repeatable error associated with faulty equipment or flawed experiment design.

Random Error: Error that arises from unpredictable variations in measurement conditions.