Describe the relation between the terms precision and accuracy in chemistry.

Accurate means how close you are to the true value. Precision means how close the measurements are to one another.

The BEST example I can think of is a dart board. 

Let's say the center of the board if you GOAL. 

Scenario 1: You throw the dart several times and it lands in the center of the board and the darts are close to one another. This means you are BOTH accurate and precise. In other words, you were close to your goal and your darts were close to one another.

Scenario 2: You throw the dart several times, and you find that the darts are nowhere close to the target but the darts are close to one another. This means that you are not accurate but you are precise. In other words, you did not reach your goal, but your darts were close to one another.

Scenario 3: You throw the darts several times, and you find that the darts are all at the center of the board but the darts aren't that close to one another. This means you were accurate but not precise.

Scenario 4: You throw the darts several times, and you find that the some of the darts are in the center, some left of it, right of it, above it, below it and none of them are close to one another. This would mean that you are neither precise nor accurate.

Another example:

Let's consider a mathematical example. Let's say you have 10 trials. Your goal is to get the number 36. 

Scenario 1: You get 36 all ten times. This means you are close to your true value and you have reached your goal.

Scenario 2: You get the number 15 nine times and you get 36 one time. This means you are not at all close to your goal, but you did get 15 many times indicating your values were close to one another.

Scenario 3: You get the number 36 for six trials, but for the other trials you get different values. This means you are accurate because, for the most part, you reached your goal. However, you would not be considered precise since the values aren't all close to one another. They are still a bit scattered.

Scenario 4: You get different values for each trial. This means your goal of getting a 36 has not been achieved and your values aren't close to each other. This scenario shows us that you were neither accurate nor precise.

Hope this helps!

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