# 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

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]
References in periodicals archive ?
The accuracy of the prediction from the test sets by the PLS-DA and sVm methods reached 100%; meanwhile, the determination coefficients of the two built models were higher than 0.96; root-mean-square errors were below 0.25, indicating that the two methods used for model building were good enough for the discrimination of the three types of meat.
The results of the regression can be interpreted in the way that the determination coefficient for this model is [R.sup.2] = 0.1753, and P statistics is 0.2856, which means greater than 0.05.
The relation model is [mathematical expression not reproducible], the determination coefficient [R.sup.2] = 0.83, the root mean square error is 0.18 m, and the value for no correlation hypothesis testing is 0, showing the correlation is significant.
The determination coefficient in both cases was [R.sup.2] [greater than or equal to] 0.988.
The calculation of their amount was based on the equation of the calibration curve: y = 0.434x (determination coefficient [R.sup.2] = 0.972).
In the light of (1) and (2), the total determination coefficient is [R.sup.2] = 0.9985.
Furthermore, a higher determination coefficient ([R.sup.2] = 0.999) for the dependence of peak current on the square root of scan rate (inset of Figure 2) than for the dependence of peak current on the scan rate indicated that the oxidation of caffeine at the modified electrode follows diffusion controlled kinetics which is in agreement with reported works .
Various statistical indices, such as P value, F value, determination coefficient ([R.sup.2]), adjusted determination coefficient (adj [R.sup.2]), and predicted determination coefficient (pred [R.sup.2]), were used to assess the statistical significance and reliability of the quadratic models .
Evans and Lyons (2002) in the model used interest rates and they show that only interest rates cannot determine exchange rate, where determination coefficient is lower than 1% and is statistically insignificant.
Under optimized conditions, the response of chemosensor 6 was linearly proportional to the concentration of Cr2O72- in a range from (10-100 uM) with determination coefficient of 0.9911.

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