Experimental Error

The process of taking any measurement always involves some uncertainty. Such uncertainty is usually called experimental error. Two methods are used to calculate the amount of error: (1) When an accepted or standard value of the physical quantity is known, percent error is calculated. (2) When no accepted value exists, percent difference is calculated.

Method 1:                           

where E_v, is the experimental value and A_v is the accepted value (known as standard value).

* Absolute difference - the smaller the value is subtracted from the larger value.

Method 2:

where                         

where E₁, E₂, and E₃ represent the experimental values and n represents the number of experimental values being averaged. Or this can be written as:

where E_L is the largest experimental value and E_s is the smallest experimental value.