Deviation

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deviation

[‚dēv·ē′ā·shən]
(engineering)
The difference between the actual value of a controlled variable and the desired value corresponding to the set point.
(evolution)
Evolutionary differentiation involving interpolation of new stages in the ancestral pattern of morphogenesis.
(optics)
The angle between the incident ray on an object or optical system and the emergent ray, following reflection, refraction, or diffraction. Also known as angle of deviation.
(petroleum engineering)
During a drilling operation, the inclination of the borehole from the vertical.
(statistics)
The difference between any given number in a set and the mean average of those numbers.

Deviation

 

in artillery, an accidental phenomenon not allowed for in the laws of dispersion, by which shells (bullets) veer away from the mean trajectory expected under the given firing conditions. Causes of deviation may be the mechanical disruption of the movement of the shell in the bore (for example, separation of the shell from the rifling grooves) or in the air (for example, a defect in the stabilizer fins or other parts), as well as a chance sharp change in weather conditions during the flight of the shell.


Deviation

 

in biology, a variety of phylembryogenesis in which a change in the development of an organ arises in the middle stages of its formation and results in a change in the structure of the organ in the adult organism, compared with the same organ in its ancestors. For example, in the middle stages of development the epidermal part of the scale buds of reptiles undergoes keratinization, not ossification (as in sharks). The term “deviation” was introduced by the German scientist F. Müller (1864).


Deviation

 

the most common measure of dispersion, that is, deviation from the mean, in mathematical statistics and theory of probability. In the statistical sense, deviation

is the arithmetic mean of the squares of the deviations of the values Xi from their arithmetic mean

In the theory of probability the deviation (variance) of a random variable X is called the expected value E(X - mx)2 of the square of the deviation of X from its expected value mx =E(X). The deviation of a random variable X is denoted by D(X) or by σ2). The square root of the deviation (that is, if the deviation is σ2) is called standard deviation.

For a random variable X with continuous probability distribution, characterized by probability density p(x), deviation is calculated by the formula

where

The following theorem has great significance in the theory of probability: the deviation of the sum of independent terms is equal to the sum of their deviations. No less important is Chebyshev’s inequality, which allows us to evaluate the probability of large deviations of the random variable X from its expected value.

REFERENCE

Gnedenko, B. V. Kurs teorii veroiatnostei, 5th ed. Moscow, 1969.

deviation

deviation
deviation
i. The angular difference between a magnetic and a compass heading. It is a compass error caused by the compass magnet attempting to align with the aircraft's local magnetic field. The deviation error changes with the aircraft heading and the latitude. It is measured in degrees east (+) or west (−), depending on whether the north-seeking end of the compass needle lies to the east or west of magnetic north.
ii. The angle between the wind and the pressure gradient.
iii. In frequency modulation, the amount the carrier increases or decreases when modulated.
vi A departure from a current clearance, such as an off-course maneuver, to avoid bad weather or turbulence.
v A variation from set rules and regulations. Where specifically authorized in the regulation and requested by the pilot, ATC (air traffic control) may permit pilots to deviate from certain regulations.
vi. In flight, a sudden excursion from the normal flight path.
vii. The distance by which a weapon misses its target.
References in periodicals archive ?
Deviational Uncertainty for PFGM project Factors derived from an ideal situation Average Response System is produced by a small group of implementers 2.
the respective weights associated with the under and over- deviational variables,
Solution Analysis of DSS for Hospital BPR Priority Goal Achievement Deviational Variables P11 = 0 Fully achieved d+17 = 12,095 P12 = 0 Fully achieved d+18 = 2,500 P21 = 0 Fully achieved d+19 = 500 P22 = 0 Fully achieved d+20 = 700 P31 = 0 Fully achieved d+21 = 3,300 P32 = 0 Fully achieved d-22 = 890 P41 = 12,095 Partially achieved d+23 = 890 P42 = 3,700 Partially achieved d+24 = 2,080 P43 = 3,300 Partially achieved P51 = 890 Partially achieved P52 = 890 Partially achieved P53 = 2,080 Partially achieved
The Standard Deviational Ellipse: An Updated Tool for Spatial Description.
However, the standard deviational ellipse for the 2001 centered value indicated that the majority of the homicide incidents drifted to the east coast, and the reporting population was more geographically dispersed than the reports of homicide.
The GP model used in the illustrative example has a single priority level and the deviational variables are given a weight of 1.
The deviational variables in the achievement function of a GP model are measured in different units.