Accuracy vs. Precision Accuracy is a description of how close a measurement is to the correct or accepted value of the quantity measured. Ex: if the correct value is 5, then 4.95 is accurate. 2 is not accurate.
Accuracy vs. Precision Precision is the degree of exactness of a measurement. Ex: If you have three measurements: 5.10, 4.95, and 4.98, they are precise. If a measurement is precise, it may not be accurate!
Significant Figures Significant figures are a way to help keep track of imprecise measurements. Significant figures are the digits that are known for certain, as well as the first digit that is uncertain. Ex: 18.2 cm has 3 significant figures. Two are known for certain, 0.2 is uncertain. It is uncertain because the digit after it is not known.
Significant Figures Rules for determining significant figures: - All whole numbers (except for zero) are significant Zeros between other nonzero digits are significant Ex: 50.3 has 3 significant figures 3.0025 has five significant figures Zeros in front of nonzero digits are NOT significant Ex: 0.892 has 3 significant figures 0.0008 has 1 significant figure Zeros that are at the end of a number and to the right of a decimal are significant. - Ex: 57.00 has four significant figures 2.000 has four significant figures