The two main types of accuracy are precision and trueness.
Precision
Precision refers to the closeness of repeated measurements to each other. It indicates the level of reproducibility and consistency of a measurement process.
- Example: If you measure the length of a table multiple times and get measurements of 2.01 meters, 2.02 meters, and 2.03 meters, the measurements are considered precise because they are very close to each other.
Trueness
Trueness, also known as accuracy, refers to the closeness of a measurement to the true or accepted value. It indicates how well a measurement reflects the actual value being measured.
- Example: If the actual length of the table is 2 meters, and you measure it as 2.05 meters, your measurement is considered accurate because it is close to the true value.
In summary:
- Precision focuses on the repeatability of measurements.
- Trueness focuses on the closeness of a measurement to the true value.
A measurement can be precise but not accurate, or accurate but not precise. Ideally, a measurement should be both precise and accurate.