An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

The difference between the measured value of a quantity x₀ and its (true) actual value x, given by Δx = x₀ - x. See also: → relative error.

→ absolute; → error.

A measurement error that remains constant in magnitude for all observations; for example an incorrectly set zero adjustment.

→ bias; → error.

A systematic error in the constant values to be applied to a measuring instrument.

→ calibration; → error.

Irang, → error; kabizeš, → calibration.

An error that amplifies as the process of calculation goes on.

→ cascade; → error.

1) A deviation from accuracy or correctness; a mistake.
2) Physics: The difference between the calculated or observed value and the true value of a quantity. See also:
→ absolute error, → bias error, → calibration error, → cascade error, → error bar, → fitting error, → instrument error, → observational error, → probable error (PE), → random error, → relative error, → root-mean-square error, → sampling error, → standard error, → systematic error, → Type I error, → Type II error.

From O.Fr. erreur, from L. errorem (nom. error) "a wandering, straying, mistake," from errare "to wander."

Irang, from Mid.Pers. êrang "error, mistake;" xatâ, from Ar.

On a graph displaying the results of a measurement, the dash used to indicate the confidence range of the value attributed to a quantity.

→ error; bar, from O.Fr. barre, from V.L. *barra "bar, barrier," or perhaps from Gaulish *barro "summit."

Band "that which closes, shuts, blocks," from bastan, band- "to shut, bind," from Mid.Pers. bastan/vastan "to bind, shut," Av./O.Pers. band- "to bind, fetter," banda- "band, tie" (cf. Skt. bandh- "to bind, tie, fasten," PIE *bhendh- "to bind;" Ger. binden; E. bind); → error.

The discrepancy between the mathematical curve and data points. → fit.

→ fitting; → error.

The correctable part of the inaccuracy of a measuring instrument.

→ instrument; → error.

The difference between a measured value of quantity and its true value.

→ observational; → error.

A deviation from the population mean μ such that 50% of the observations may be expected to lie between μ - PE and μ + PE. For the normal distribution, the probable error is 0.6745 times the standard deviation.

→ probable; → error.

The fluctuating part of the overall error that varies from measurement to measurement. Normally, the random error is defined as the deviation of the total error from its mean value; opposite of → systematic error.

→ random; → error.

The → absolute error divided by the true value x, that is: Δx/x. The result may be expressed as a percentile and is useful when we want to determine the error relative to the value of the exact quantity.

→ relative; → error.

The square root of the second moment corresponding to the frequency function of a random variable.

→ root; → mean; → square; → error.

That part of the difference between a population value and an estimate thereof, derived from a random sample, which is due to the fact that only a sample of values is observed; as distinct from errors due to imperfect selection, bias in response or estimation, errors of observation and recording, etc.

→ sampling; → error.

Same as → standard deviation.

→ standard; → error.

The error that is constant in a series of repetitions of the same experiment or observation. Usually, systematic error is defined as the expected value of the overall error. opposite of → random error.

→ systematic; → error.

Statistics: An error made if a → hypothesis is rejected when it should be accepted. → Type II error.

→ type; → error.

Statistics: An error made if a → hypothesis is accepted when it should be rejected. → Type I error.

→ type; → error.