Accuracy and Precision

In our chemistry class, we have recently discussed the importance of accuracy, precision, and significant digits. When using every day terms, accuracy and precision are considered to be synonymous. In the world of science, this couldn’t be less true. Accuracy is defined in the scientific world as the closeness of a measurement of a quantity to that quantity’s actual value. On the other hand, precision is related to the degree in which repeated measurements under unchanged conditions result in the same data. This means that the two are actually quite different, although they may at first appear similar.

http://dl.clackamas.cc.or.us/ch104-01/accuracy_vs_precision.htm

The image above displays the differences between accuracy and precision.

Significant digits are a closely related topic. “Sig-Digs”, as they are termed, play very important roles in accuracy and precision. When measuring data in lab, they are crucial to recording precise measurements. Significant digits impact how precise a measurement is, and the number of sig digs present impacts to which place a number is accurate. For example, if you have .5809, the 9 lets you know that the number is accurate to the ten thousandths place.  Regarding precision, sig digs are utilized in making sure measurements are “spot on”. If you are measuring a weight and you see that while the scale only measures to the .1, but you can visually see that the weight falls between marks, you can measure to the .01 in order to make the number more precise.

http://www.youtube.com/watch?v=VAuslY-Uuf4

The link above is a video that explains the importance of significant digits in further detail.

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