SAB7#077 Precision vs Accuracy

SAB7#077 Precision vs Accuracy

1. Precision is a measure of exactness

   • An experiment to measure the temperature at which water boils. You set up three containers of water and heat each one. At the instant the water boils you measure the temperature and get the following results: 67°C, 68°C, 68°C, 65°C, and 66°C. Notice these values are precise (they are almost the same, they agree with each other), but they are not accurate. They would have to be at about 100°C, the accepted value, to be accurate.

2. Accuracy is an assessment of correctness

   • An example of accuracy is a GPS

3. Often they are confused as synonyms

4. For quality purposes, accuracy is desired

5. For accuracy, one measurement is enough; however, for precision many measurements are required.

Images and files in the map