Differentiate accurate from precise in measurement?

Answer 1

Accuracy is when the result is close or equal to the actual value or expected result. Precision is when multiple results are within the same or very close value. With multiple results, you can have accuracy and precision if the results are on target, and all within a very close range. However, if the results have quite a bit of deviation among them, but the average result is on target, then you have accuracy, but low precision. If multiple results are way off target, but are all within a close range of each other, then you have low accuracy and high precision. If the multiple results are all over the place, and the average result is off target, then you have low accuracy and low precision. For example, it helps to imagine a dart board with a few darts. If all the darts are together after being thrown, that is precision. When the thrown dart is close to the bullseye, that is accuracy. IF the darts are all close together and all on the bullseye - that is accurate and precise...if they are all close together, but way off the bullseye, then that is precise but NOT accurate, and so on...