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Accuracy and Precision

In science, engineering, and statistics, accuracy and precision are distinct concepts. The accuracy of a measurement system is the degree of closeness of measurements of a quantity to that quantity's true value, which is a function of the inherent variability of the measurement system. The precision of a measurement system, also called reproducibility or repeatability, is the degree to which repeated measurements under unchanged conditions show the same results.


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Video Transcript

Whenever you collect data for an experiment, the values that you get from your measurement can be accurate or inaccurate and precise or imprecise. So inaccurate value is defined as a measure of value that is the true value. So, for example, if you measure the length of a pencil that is five inches and the actual length of the pencil is five inches long, your measurement was accurate. Precise valleys. Sorry, um, precise values are defined as a set of measured values that are close to each other. So, for example, if you throw a ball 3 ft away once 3.2 ft away again and 3.1 ft afterwards you're throwing is precise because the distances obtained are close to one another. Eso to demonstrate how certain pieces of data can be both inaccurate and imprecise, accurate and imprecise, an accurate and precise and both accurate and precise. I'll be using a dart and board analogy to explain this. So the first case for something that is inaccurate and imprecise. This means that the darts are basically hitting all over the board, but not at the center point which will represent the act provides. So let's say I have five darts and they're positioned in this manner. We can describe this set of data as not accurate and not precise again because the data points are far apart from one another. And it's not hitting the center point, which represents where the accurate value it's. So for the next example, if something is accurate and not precise, we'll see that the darts are hitting the center point, which is the accurate value. However, the dart are not very close to one another. They're kind of clothes, but in this case, we can say that they're far apart enough so that they're not precise for something that is not accurate but precise. We can imagine a cluster of darts in one section of the board, um, so you can see that the darts are very precise because they're cluster together and they're very close to each other. Have, er, thes darts are not accurate because the accurate value is here and the not accurate value is basically away from the border. And so, for our last example for something that is accurate and both precise, we'll have a cluster of darts at theseventies point so that the points are close to one another and are also at the center of the board, which is where the accurate value is.