Accuracy, Percent Error, Absolute Value

 Accuracy refers to how close a measurement comes to the accepted value for a physical quantity.  (Accepted values are recorded in such books as The Handbook of Physics and Chemistry)

Absolute error is the difference between your experimental value and the accepted value.

   Example: 

        Experimental value for melting point of substance  =  51^oC

        Accepted value for melting point of substance        =  53 ^oC

        Absolute Error  =  2 ^oC

        Percentage Error is