Robin reaction dot com! In this video. I'm going to talk about the differences between accuracy and precision two different ways that we measure how good our results are and So just some definitions, that'll do a bunch of examples accuracy is how close a measured value is to the actual value and Precision is how close the measured values are to each other. All right, don't think about that too hard Let's just do the examples and then I'll go back to the definitions so I'm gonna be doing an example using a dartboard which I think is one of the best and easiest ways to Understand the two differences between these two concepts. You may have seen it before and sometimes People just learn what the best analogy is and then you just roll with that. So I definitely think this one is worth learning so over here in our little gray box, we're going to look at the actual value so we know if we're trying to Throw something at a dartboard. We're looking to get a bull's eye, right? This is the goal So now we're gonna say that we have four different darts and in these four tries we're going to do the best that we can so our first example is going to be low accuracy and low precision So for low accuracy, that means that our actual tries are not close at all to the center So maybe our four darts would end up like this All right, this was very very Inaccurate we didn't get anything close to the bull's eye and this is also a very low precision Guess because remember the precision is how close the measured values are to each other So not only were these darts not accurate. They also weren't close to each other. They also weren't precise All right So now we're going to do our second throw of the dartboard and this is going to be low accuracy but high precision So it's going to not be accurate We're not going to get the center of the dartboard But it's going to be precise the are going to be close to each other So something that will look like that is maybe a guess like this So this was super precise all the darts got in the same a got about in the same place Very very precise all of the values are close to each other, but it's low accuracy, right? They're not close to what we wanted which was the center of the board So now next let's do high accuracy low precision So in this case, we're going to get close to the center, but we're not going very precise. So that would be something like this All right, so yeah the darts are pretty accurate You would look at this and say that's pretty good But they weren't really that close to each other so they weren't very precisely at low precision And now let's see the best-case scenario of all the show of all these throws which is high accuracy and high precision So we're going to get in the middle of the dartboard and they're also going to be really close to each other So that would be like this Very accurate very precise Okay, so that's kind of an analogy. That's easy to understand visually I think and kind of helps us start to get this concept but in chemistry or science We're not going to be really throwing dart boards So let's actually learn something that this that these concepts will be tested towards and in a lot of cases It's going to be weighing something or getting the mass of something All right. So now let's say we're going to weigh a random cube cube of silver let's say and let's say that we actually know the exact value of it or your teacher does or somehow we just Know that this value is exactly 5.00 grams. So now let's go through the four different scenarios that we could get all right, so first and and for this example Let's say that it's your job to measure this cube four different times in lab and report your results So let's say our first example is again low Accuracy and low precision so we weigh the cube four different times and here is what we get All right, so we got six point three two grams three point, oh one grams seven point five five grams and four point Oh two grams. So none of these were that close to five grams, and they also Weren't close to each other So they were very low accuracy and they were very low precision if this is what you got when you weighed this cube five times You should really get your scale fixed or throw it away or check your technique, right? Something is very wrong if these zero results, so now let's do the next one, which is low accuracy So it's still not going to close to five grams, but it's high precision Alright so we got eight point three two grams eight point three five grams eight point two nine grams and eight point three two grams So in this situation, we are super precise. It's just like the darts They're all very close to each other, but it's not accurate at all. It's not correct so in this situation You probably have something specifically wrong with your scale or your keep on adding something else to it that you don't realize Right. So in this case the scale may be able to get fixed Maybe it just adds about three point three grams to anything you weigh, but whatever you want to do You also wouldn't want to use this scale, right? And now let's do a high accuracy, but low precision measuring four times So we're going to be getting close to the actual value, but it's not going to be super precise The values are going to be a little bit all over the place. So maybe that looks like something like this So we had five point one five grams four point seven seven grams five point two eight grams and 5.00 grams So all of these were pretty close to the actual value But they weren't close to each other right The range went all the way from four point seven seven to five point two eight Not super precise just generally in the ballpark of being accurate Again, if this is what your scale is giving you Maybe it's just kind of a really cheap scale like it's kind of knows what's up But it also gets things like not close to each other so far I would not want to use any of these three scales and lab I'd throw them all away and then steal a good scale from Someone who had one. All right So now let's do the only scale we want to use it's gonna be highly accurate and highly precise So let's say our four values are something like this 5.01 grams four point nine nine grams 5.00 grams and 5.00 grams So this is great, right. This is what you want to do If you measure something four times, you get the same thing almost every time and it should be the actual mass of What you're measuring and so this is both highly accurate and highly precise Alright, hope this video helped you understand the difference between accuracy and precision I would keep on going back to the dartboard and really staring at those guys if they kind of don't make sense to you and I used I like to think about the dart boards if I ever kind of I'm having trouble knowing if something is accurate or precise And happy studying. Hey, I hope you liked that video Please feel free to like comment or subscribe and if you go to my website I have a ton of free practice problems. You can check out if you need even more help You can hire me for one on one private tutoring sessions that are online Alright, thanks. That's it. Happy studying