Science and Experiments
When either randomness or uncertainty modeled by probability theory is attributed to such errors, they are "errors" in the sense in which that term is used in statistics; see errors and residuals in statistics.
Every time we repeat a measurement with a sensitive instrument, we obtain slightly different results. The common statistical model we use is that the error has two additive parts:
- systematic error which always occurs, with the same value, when we use the instrument in the same way and in the same case, and
- random error which may vary from observation to observation.
The systematic error is sometimes called statistical bias. It is controlled by very carefully standardized procedures. Part of the education in every science is how to use the standard instruments of the discipline.
The random error (or random variation) is due to factors which we cannot (or do not) control. It may be too expensive or we may be too ignorant of these factors to control them each time we measure. It may even be that whatever we are trying to measure is changing in time (see dynamic models), or is fundamentally probabilistic (as is the case in quantum mechanics -- see Measurement in quantum mechanics). Random error often occurs when instruments are pushed to their limits. For example, it is common for digital balances to exhibit random error in their least significant digit. Three measurements of a single object might read something like 0.9111g, 0.9110g, and 0.9112g.
Read more about this topic: Observational Error
Famous quotes containing the words science and, science and/or experiments:
“In our science and philosophy, even, there is commonly no true and absolute account of things. The spirit of sect and bigotry has planted its hoof amid the stars. You have only to discuss the problem, whether the stars are inhabited or not, in order to discover it.”
—Henry David Thoreau (1817–1862)
“Until politics are a branch of science we shall do well to regard political and social reforms as experiments rather than short-cuts to the millennium.”
—J.B.S. (John Burdon Sanderson)
“The man who invented Eskimo Pie made a million dollars, so one is told, but E.E. Cummings, whose verse has been appearing off and on for three years now, and whose experiments should not be more appalling to those interested in poetry than the experiment of surrounding ice-cream with a layer of chocolate was to those interested in soda fountains, has hardly made a dent in the doughy minds of our so-called poetry lovers.”
—John Dos Passos (1896–1970)