Precision

Definition

Precision is the degree to which repeated measurements under unchanged conditions show the same results. It indicates the consistency and repeatability of measurements.

5 Must Know Facts For Your Next Test

1. Precision is different from accuracy, which refers to how close a measured value is to the true value.
2. High precision means that the values of repeated measurements are very close to each other.
3. Precision is often expressed using standard deviation or variance.
4. A measurement can be precise but not accurate if it consistently produces similar results that are far from the true value.
5. In scientific experiments, precision improves with more trials and better instruments.

Review Questions

• What does high precision indicate about repeated measurements?
• How can a measurement be precise but not accurate?
• What statistical tools are commonly used to express precision?

Related terms

Accuracy:

The degree to which a measured value is close to the true or accepted value.

Significant Figures:

Digits in a number that contribute to its precision, including all certain digits and one uncertain digit.

Standard Deviation:

A measure of the amount of variation or dispersion in a set of values, often used to quantify precision.