Example: You want to know how accurately you estimate distances by pacing them off. You pace from one tree to another and estimate that they’re 18 feet apart. This is the experimental value. Then you come back with a long measuring tape to measure the exact distance, finding out that the trees are in fact 20 feet (6 meters) apart. That is the “real” value. Your absolute error is 20 - 18 = 2 feet (60. 96 centimeters).

This works for any measurement system. Many scientific tools, like precision droppers and measurement equipment, often has absolute error labeled on the sides as “+/- ____ "

Jill is studying chemical reactions. After mixing and matching, her test tube contains 32 grams of substrate. The accepted value for her experiment was 34 grams. Her Absolute Error is: +/- 2 grams Clive is testing reactions in chemistry. It takes 10ml drops of water to cause a reaction, but his dropper claims it is “+/- . 5ml. " The Absolute Error in his measurements must be: +/- . 5ml

Human error is the most common. This is from bad measurements, faulty premises, or mistakes in the lab. Incidental energy/material loss, such as the little fluid left in the beaker after pouring, changes in temperature due to the environment, etc. Imperfect equipment used either for measurement or studies, such as very small, precise measurements or burners that provide uneven heat. [3] X Research source

Note that in most cases the unit of measurement of the absolute error will be the same as the unit of measurement of the actual value, and the units will cancel each other. This leaves the relative error without any units of measurement. This simple equation tells you how far off you were in comparison to the overall measurement. A low relative error is, of course, desirable. To continue the example of measuring between two trees: Your Absolute Error was 2 feet, and the Actual Value was 20 feet. 2ft20ft{\displaystyle {\frac {2ft}{20ft}}} Relative Error =. 1{\displaystyle =. 1}

2ft20ft=. 1{\displaystyle {\frac {2ft}{20ft}}=. 1} . 1∗100=10%{\displaystyle . 1*100=10%} Relative Error.

Relative Error =|Measured−Actual|Actual{\displaystyle ={\frac {|\mathrm {Measured} -\mathrm {Actual} |}{\mathrm {Actual} }}} Multiply the whole thing by 100 to get Relative Error Percentage all at once. [7] X Research source