Question

What is the difference between accuracy and precision? Please provide an example without using the example of darts/target board.

Answer 1

Oh dear. I'll do my best to provide an example, so I just pray it helps you better than the classic target board example.

First of all, accuracy is how close you get to your goal. Precision is how close your attempts to reach your goal are to each other.

For example, take a chemistry experiment (since you posted this in the chemistry section xD). Your goal in the experiment is to use the following chemical reaction (you don't need to know what the chemicals are, just how the reaction works: two chemicals, NaCl and AgNO3, are combined to make the chemical NaNO3 and the solid stuff AgCl)

NaCl(aq) + AgNO3(aq) → NaNO3(aq) + AgCl(s)

Through some calculations (which are probably wrong in my example), you find that, when you combine a liter of NaCl and a liter of AgNO3, you should get a liter of NaNO3. You decide to test this out by actually putting a liter of each together.

Your result was 0.9 liters of NaNO3. This means you missed what you thought you would get (1.0 liters of NaNO3) by about 10%. In the chemistry world, that's not a small error (but not always a big one either). Since you missed by a good amount, you'd say that your process was inaccurate. (Maybe one of the beakers you used was labeled incorrectly, who knows?)

However, if you consistently got 0.9 liters after trying again and again, this means that you probably have done it exactly the same way (with the exact same issues) time after time. This means that your experiment was pretty precise, since you failed the SAME way each time.

In this experiment, you weren't accurate (since you didn't get what you thought you would get from the experiment), but you were precise (you didn't get what you want time and time again because you had the SAME or SIMILAR issues and RESULTS.)

Sorry if my example's complicated/too similar to the target board example. I thought I'd just take a crack at trying to help.