Deviation

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Related to axis deviation: Right Axis Deviation, left axis deviation

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

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 ?
In Group A, 9 (21.9%) patients showed evidence of right axis deviation. 2 patients (4.7%) had low voltage, 4 (9.5%) had atrial ectopic, 2 (4.7%) had ventricular ectopic.
Caption: Figure 1: EKG on presentation showing right axis deviation and ST-T wave changes.
Regular follow up and early interpretation of ECG on the basis of left axis deviation, QRS complex and ST changes altogether help to start early treatment of disease.
2: Electrographic Profile of Patients at the Time of Presentation ECG Parameters Frequency of ECG findings Ventricular hypertrophy Both 1 RVH 1 LVH 12 Atrial enlargement RAE 2 LAE 3 ST-T 4 Arrhythmias RBBB 3 LBBB 5 Complete heart block 0 Ventricular tachycardia 2 Ventricular ectopics 4 SVT 3 Atrial fibriliation 3 Atrial ectopics 4 Sinus tachycardia 19 QRS axis Right axis deviation 2 Left axis deviation 4 Normal 18 Note: Table made from bar graph.
Electrocardiogram (ECG) can be used for screening of COPD with most common parameters observed may be right axis deviation, P pulmonale and right ventricular hypertrophy.
Electrocardiogram showed unexpectedly tall "P" waves (9 mm in lead V2) and right axis deviation (Fig.
Marked right axis deviation of the QRS with a qR pattern in lead V1 suggests severe right ventricular hypertrophy, probably due to right ventricular systolic pressure at or above systemic level.
ECG evidence of P-pulmonale in 51%, right axis deviation in 45% and RVH in 39% of patient is comparable with findng of S.
The QRS is negative in lead I and positive in lead aVF, indicating right axis deviation, and a QRS more negative in lead I than in aVR suggests that the QRS axis is closer to + 120[degrees] than to + 90[degrees].
Criteria for left anterior fascicular block as proposed by the World Health Organization/International Society and Federation of Cardiology (WHO/ISFC) task force are left axis deviation of the QRS in the frontal plane of -45[degrees] to -90[degrees], qR pattern in aVL, R peak time in aVL [greater than or equal to] 45 ms, and QRS duration <0.12s.

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