Precision and accuracy are the terms that are used in chemistry when we want to describe a measurement’s quality.
Precision is indicating the reproducibility degree of any measured quantity.
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Precision is depending on how good we are at making measurements.
Accuracy is providing a measure of and in what way the measured value comes close to the true value. It depends on the calibration and quality of the used measuring device.
Here is an example: Let’s say, just for conversation’s sake, that you’re working in a circus and are guessing the weight of people.
A good method of measurement would be to have them come and sit on your lap.
Let’s assume the same person will come back four times in the course of that day, and every time, you guess different weights.
When that person’s true weight would be 60 kg (or 132 lbs), and your guesses are:
• 65 kg
• 70 kg
• 56 kg
• 51 kg
• Average: 60.5
These numbers are representing good accuracy yet pretty poor precision.
When on the other hand, your guesses would have been:
• 68 kg
• 67 kg
• 69 kg
• 68 kg
• Average: 68 kg
The numbers would have represented pretty poor accuracy but actually good precision.
So again, accuracy and precision are terms used in chemistry to describe the quality of a measurement.
Precision indicates the reproducibility degree of measured quantities and depends on how well we make the measurements.
Accuracy provides a measure of how close a measured value is to the true value and depends on the quality and calibration of the used measuring devices.