Accuracy vs Precision

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alexfwang3g
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Joined: Thu Jul 11, 2019 12:16 am

Accuracy vs Precision

Postby alexfwang3g » Sun Sep 29, 2019 1:19 pm

I know that in everyday language, these two terms can be interchangeable. What is the primary difference between the two terms in chemistry.

JasonLiu_2J
Posts: 109
Joined: Sat Aug 24, 2019 12:17 am

Re: Accuracy vs Precision

Postby JasonLiu_2J » Sun Sep 29, 2019 1:30 pm

Accuracy refers to how close your measurements or results are to a predetermined or accepted value. For example, if the accepted mass of a weight is 5 grams and your measurement is, say, 5.1 grams, then the result would be accurate. Precision on the other hand refers to how close your measurements or results are to one another. If you conduct 5 different trials and obtain 8 grams in each of them for the 5g mass, then the results would be precise, since they are close to one another, but not accurate. However, if your results are all within say 0.01 grams of the 5 gram accepted value, then the results would be both precise and accurate.

Megan Vu 1J
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Joined: Thu Jul 25, 2019 12:15 am

Re: Accuracy vs Precision

Postby Megan Vu 1J » Sun Sep 29, 2019 7:20 pm

In lecture, precision refers to how close to one another measurements are. For accuracy, it refers to the closeness to the true value. For example, a bullseye target is able to show the differences between accuracy and precision. If a bullseye target has dots close together in the center, this means that it has high accuracy and high precision. However, if a bullseye target has dots close together but located in the top, it shows low accuracy and high precision. If a bullseye target has dots spread far apart but located in the center, it shows high accuracy and low precision. Ultimately, if a bullseye target has dots spread far apart and not located in the center, it has low accuracy and low precision. Hope this analogy helps!

Matthew ILG 1L
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Joined: Sat Aug 17, 2019 12:15 am

Re: Accuracy vs Precision

Postby Matthew ILG 1L » Sun Sep 29, 2019 7:22 pm

Dr. Lavelle showed this same image during the lecture last Friday, September 27th, and I found it to be very helpful and informative.

https://www.google.com/url?sa=i&source= ... 6427836057

Jialun Chen 4F
Posts: 108
Joined: Sat Sep 07, 2019 12:16 am

Re: Accuracy vs Precision

Postby Jialun Chen 4F » Sun Sep 29, 2019 11:57 pm

Precision is how close to each other the measurements are. You can have high precision but still got a bad lab trial because of both data are flawed. Accuracy is how close measurements are to the correct value.

Mandeep Garcha 2H
Posts: 100
Joined: Sat Aug 24, 2019 12:17 am

Re: Accuracy vs Precision

Postby Mandeep Garcha 2H » Mon Sep 30, 2019 9:41 pm

Professor Lavelle used this picture:
http://cdn.antarcticglaciers.org/wp-con ... curacy.png
on his powerpoint which I felt was very helpful in understanding the difference between the two.

Chetas Holagunda 3H
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Joined: Thu Jul 11, 2019 12:17 am
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Re: Accuracy vs Precision

Postby Chetas Holagunda 3H » Mon Sep 30, 2019 9:58 pm

Precision refers to how close your measurements are to each other while accuracy represents how close to the true value the measurements are. Adding on, although your measurements may be thrown off because of a systematic error (e.g. the weighing scale is not calibrated correctly), they can be accounted for if your measurements are precise.

Justin Vayakone 1C
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Joined: Sat Sep 07, 2019 12:19 am

Re: Accuracy vs Precision

Postby Justin Vayakone 1C » Mon Sep 30, 2019 11:57 pm

A simple way for me to figure out the difference between these two terms is to think of precision as consistency and accuracy as the bullseye of a target.

Jesse H 2L
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Re: Accuracy vs Precision

Postby Jesse H 2L » Tue Oct 01, 2019 12:18 am

precision is consistent results while accuracy is how close to the true value we can get.

Jocelyn Thorp 1A
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Joined: Wed Sep 18, 2019 12:20 am

Re: Accuracy vs Precision

Postby Jocelyn Thorp 1A » Tue Oct 01, 2019 12:40 am

Jesse H 3 wrote:precision is consistent results while accuracy is how close to the true value we can get.


this response is succinct and how I'm going to think of it from now on. thanks

britthanul234
Posts: 51
Joined: Wed Sep 18, 2019 12:21 am

Re: Accuracy vs Precision

Postby britthanul234 » Tue Oct 01, 2019 8:33 am

I think the best way to think of the difference between accuracy and precision is to visualize the different examples of the target that Professor Lavelle gave during class. Precision is how close the measurement are to one another, so something can be very precise without having to be close to the target. Accuracy is how close it is to its true value, so the target does apply here.


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