| English | Precision |
|---|---|
| Bahasa Melayu | Kepersisan |
| 中文 | 精密度 |
Definition
The ability of an instrument to give consistent, closely grouped readings when a measurement is repeated.
In exam terms
Precision is the ability of an instrument to give readings that are consistent and closely grouped when a measurement is repeated. A precise instrument produces values with little scatter, and usually has smaller scale divisions.
For example, a vernier caliper reading to 0.01 cm is more precise than a metre rule reading to 0.1 cm. Precision is limited by random error.
A correct sentence: The five repeated readings 4.51, 4.52, 4.51, 4.52, 4.51 cm are precise because they are closely grouped.
Do not confuse it with accuracy
Do not confuse precision with accuracy. Precision is about how consistent repeated readings are; accuracy is about how close a reading is to the true value.
Readings can be precise but not accurate if there is a zero error, since they cluster tightly around the wrong value.
In Paper 2, a question may ask you to compare precision and accuracy, or to choose the more precise instrument. Always link precision to consistency and smaller scale divisions, and accuracy to the true value.
Source: DSKP KSSM Physics Form 4 and 5 (Versi English) (Bahagian Pembangunan Kurikulum (BPK), KPM)