# coefficient

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## coefficient

[ko″ĕ-fish´ent]
1. an expression of the change or effect produced by the variation in certain variables, or of the ratio between two different quantities.
2. in chemistry, a number or figure put before a chemical formula to indicate how many times the formula is to be multiplied.
absorption coefficient absorptivity.
Bunsen coefficient the number of milliliters of gas dissolved in a milliliter of liquid at atmospheric pressure (760 mm Hg) and a specified temperature. Symbol, α.
confidence coefficient the probability that a confidence interval will contain the true value of the population parameter. For example, if the confidence coefficient is 0.95, 95 per cent of the confidence intervals so calculated for a large number of random samples would contain the parameter.
correlation coefficient a numerical value that indicates the degree and direction of relationship between two variables; the coefficients range in value from +1.00 (perfect positive relationship) to 0.00 (no relationship) to −1.00 (perfect negative or inverse relationship).
diffusion coefficient see diffusion coefficient.
coefficient of digestibility the proportion of a food that is digested compared to what is absorbed, expressed as a percentage.
dilution coefficient a number that expresses the effectiveness of a disinfectant for a given organism. It is calculated by the equation tcn = k, where t is the time required for killing all organisms, c is the concentration of disinfectant, n is the dilution coefficient, and k is a constant. A low coefficient indicates the disinfectant is effective at a low concentration.
linear absorption coefficient the fraction of a beam of radiation absorbed per unit thickness of absorber.
mass absorption coefficient the linear absorption coefficient divided by the density of the absorber.
phenol coefficient see phenol coefficient.
sedimentation coefficient the velocity at which a particle sediments in a centrifuge divided by the applied centrifugal field, the result having units of time (velocity divided by acceleration), usually expressed in Svedberg units (S), which equal 10−13 second. Sedimentation coefficients are used to characterize the size of macromolecules; they increase with increasing mass and density and are higher for globular than for fibrous particles.

## co·ef·fi·cient

(kō'ĕ-fish'ĕnt),
1. The expression of the amount or degree of any quality possessed by a substance, or of the degree of physical or chemical change normally occurring in that substance under stated conditions.
2. The ratio or factor that relates a quantity observed under one set of conditions to that observed under standard conditions, usually when all variables are either 1 or a simple power of 10.
[L. co- + efficio (exfacio), to accomplish]

## coefficient

/co·ef·fi·cient/ (ko″ah-fish´int)
1. an expression of the change or effect produced by variation in certain factors, or of the ratio between two different quantities.
2. a number or figure put before a chemical formula to indicate how many times the formula is to be multiplied.

absorption coefficient
biological coefficient  the amount of potential energy consumed by the body at rest.
correlation coefficient  a measure of the relationship between two statistical variables, most commonly expressed as their covariance divided by the standard deviation of each.
linear absorption coefficient  in radiation physics, the fraction of a beam of radiation absorbed per unit thickness of the absorber.
mass absorption coefficient  in radiation physics, the linear absorption coefficient divided by the density of the absorber.
phenol coefficient  a measure of the bactericidal activity of a chemical compound in relation to phenol.
sedimentation coefficient  the velocity at which a particle sediments in a centrifuge relative to the applied centrifugal field, usually expressed in Svedberg units (S), equal to 10−13 second, which are used to characterize the size of macromolecules.
coefficient of thermal conductivity  a number indicating the quantity of heat passing in a unit of time through a unit thickness of a substance when the difference in temperature is 1°C.
coefficient of thermal expansion  the change in volume per unit volume of a substance produced by a 1°C temperature increase.

## coefficient

[kō′efish′ənt]
Etymology: L, cum, together with, efficere, to effect
a mathematic relationship between factors that can be used to measure or evaluate a characteristic under specified conditions. Examples include Henry's law, which measures solubility coefficient; Graham's law, which calculates diffusion coefficient; and the oxygen-utilization coefficient, which measures the amount of oxygen in a patient's venous blood in terms of the proportion of oxygen in his or her arterial blood.

## coefficient

Vox populi A variable or factor which allows the calculation of a property or quantity of a substance under various conditions. See Absorption coefficient, Activity coefficient, Adsorption coefficient, Attenuation coefficient, Dice coefficient of similarity, Inbreeding coefficient, Intraclass correlation coefficient, Mass attentuation coefficient, Mass energy absorption coefficient, Octanol-water partition coefficient, Spearman's rank (order) correlation.

## co·ef·fi·cient

(kō'ĕ-fish'ĕnt)
1. The expression of the amount or degree of any quality possessed by a substance, or of the degree of physical or chemical change normally occurring in that substance under stated conditions.
2. The ratio or factor that relates a quantity observed under one set of conditions to that observed under standard conditions, usually when all variables are either 1 or a simple power of 10.
[L. co- + efficio (exfacio), to accomplish]

## coefficient

1. an expression of the change or effect produced by the variation in certain factors, or of the ratio between two different quantities.
2. in chemistry, a number or figure put before a chemical formula to indicate how many times the formula is to be multiplied.

absorption coefficient
1. the fraction of a beam of radiation that is absorbed in passing through a unit length of absorbing material.
2. a number indicating the volume of a gas absorbed by a unit volume of a liquid at 32°F (0°C) and at a pressure of 760 mmHg.
alienation coefficient
a measure of the lack of association between two variables. Called also the coefficient of nondetermination.
Bunsen coefficient
see absorption coefficient (2) (above).
contingency coefficient
a measure of association between qualitative assessments of two variables.
correlation coefficient
a measure of association which indicates the degree to which two or more sets of observations fit a linear relationship. Denoted by 'r', it can vary from −1.0 to 1.0.
determination coefficient
the coefficient of determination is the square of the correlation coefficient (r2). It describes the proportion of the variation of one of the correlated variables, explainable by the variation of the other variable. The value of the coefficient must lie between 0 and 1.
digestibility coefficient
percentage of the food ingested that is absorbed.
disarray coefficient
the measure of the degree of discord between two variables.
friction coefficient
the effect that the material in a surface has on the frictional force created by the application of a force to the surface: S = f × N, where S = friction, f = friction coefficient, N = reaction to the vertical application of a given force. In a normal joint the f value is very small (0.008).
coefficient of nondetermination
see alienation coefficient.
References in periodicals archive ?
5,4] transition is a too large (measured from the base) and the mass absorption coefficient decreases somewhat too rapidly past the [M.
Reference [9] reports a measurement of the mass absorption coefficient of thin film Ta samples at 1486.
As shown below, the new values for the tungsten mass absorption coefficient are in better agreement with the bulk of previous theory and experiment than are the values of Ref.
For multi-element samples the calculations of average mass absorption coefficients and average stopping power are properly formulated using mass fractions in traditional expressions because the terms are grounded in mass units.

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