# correlation 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.

## cor·re·la·tion co·ef·fi·cient

a measure of association that indicates the degree to which two variables have a linear relationship; this coefficient, represented by the letter r, can vary between +1 and -1; when r = +1, there is a perfect positive linear relationship in which one variable relates directly with the other; when r = -1, there is a perfect negative linear relationship between the variables.

## cor·re·la·tion co·ef·fi·cient

(kōrĕ-lāshŭn kōĕ-fishĕnt)
Measure of association that indicates the degree to which two variables have a linear relationship.

## cor·re·la·tion co·ef·fi·cient

(kōrĕ-lā shŭn kōĕ-fishĕnt)
Measure of association that indicates degree to which two variables have a linear relationship.

## 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.

## correlation

1. in neurology, the union of afferent impulses within a nerve center to bring about an appropriate response.
2. the degree to which statistical variables vary together.

correlation coefficient
see correlation coefficient.
References in periodicals archive ?
Ye ([18],[19]) established a model for weighted correlation coefficient between each alternative and the ideal alternative for single valued neutrosophic sets (SVNSs) using known weights of the criterion.
The relationship between German RWAP and HPI is not strong, with a correlation coefficient of 0.
Table 4: The correlation coefficients between the photosynthetic characteristics and yield traits and drought resistance index of spring wheat under two different water conditions
So path coefficient analysis technique is a statistical approach which is based on multiple regression and is useful for revealing the direct and indirect effects of the variables in a network of factors like agro/morpho/physio/biochemical traits which is able to separate correlation coefficients into their components of direct and indirect effects (Dewey and Lu, 1959; Wright, 1960).
The correlation coefficients obtained between (a *) and the other parameters are shown in Table 4.
The standard correlation coefficients reported on table 1 are in all cases calculated using information that covers two variables for each coefficient.
Of 33 pleural fluid samples analysed, excellent agreement was found when counting WBCs by both the methods with a correlation coefficient being 0.
Correlation coefficients were also calculated between all the contact angle measurements and the subsequently calculated surface energy values to determine if a correlation coefficient is a suitable calculation to determine mathematical relationships between stain repellency and contact angle.
Correlation coefficients were calculated between observed arch widths and those predicted according to Pont's indices.
The correlation coefficient can be used to analyse the likeliness criteria of two signals.
In this paper, we use Pearson's correlation coefficient to calculate correlation coefficients for fuzzy interval data.
The main work can be divided into three parts: (1) the basic research on the relationship between carbon emissions and economic growth, including the Cointegration and Granger causality; (2) Using the dynamic correlation multivariate stochastic volatility model (DC-MSV model) to extract correlation coefficient between carbon emissions and Chinese gross domestic product (GDP); (3) Using the regression analysis method to study the prediction ability of the dynamic correlation coefficient on the Chinese green economic growth rate.

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