Accuracy vs. Precision

·         Accuracy: The "trueness" or the closeness of the analytical result to the "true" value. It is constituted by a combination of random and systematic errors (precision and bias) and cannot be quantified directly. The test result may be a mean of several values. An accurate determination produces a "true" quantitative value, i.e. it is precise and free of bias.
         Accuracy: A measure of how close an experimental result is to the true value.
         Accuracy refers to the degree of conformity and correctness of something when compared to a true or absolute value
         Accuracy refers to how closely the measured value of a quantity corresponds to its "true" value.
          Accuracy means getting a result that is close to the real answer

·         Precision: The closeness with which results of replicate analyses of a sample agree. It is a measure of dispersion or scattering around the mean value and usually expressed in terms of standard deviation, standard error or a range (difference between the highest and the lowest result).
         Precision: A measure of how exactly the result is determined.  It is also a measure of how reproducible the result is.
1. Absolute precision: indicates the uncertainty in the same units as the observation
2. Relative precision: indicates the uncertainty in terms of a fraction of the value of the result
·         precision refers to a state of strict exactness.
·         Precision expresses the degree of reproducibility or agreement between repeated measurements.
·          Precision means getting a similar result every time you try.