“parameter”的概念、定义、翻译、参考文献-科学参考

parameter

Statistics

A constant appearing as part of the description of a probability function or the probability density function of a family of distributions. The shape of the distribution depends on the value(s) given to the parameter(s). For example, the parameters of a binomial distribution are n and p, the parameter of a Poisson distribution is λ, the parameters of a normal distribution are μ and σ, and ν is the parameter of both a chi-squared distribution and a t-distribution. The term is also used more widely; for example it is used to describe the unknowns (α, β) in linear regression and the corresponding terms in the multiple regression model. The word ‘parameter’, in a statistical context, was first used by Sir Ronald Fisher in 1922.

Chemical Engineering

A variable whose characteristic is not considered and may therefore be taken as being constant.

Computer

1. Information passed to a subroutine, procedure, or function. The definition of the procedure is written using formal parameters to denote data items that will be provided when the subroutine is called, and the call of the procedure includes corresponding actual parameters. See also parameter passing.
2. A quantity in a function or mathematical model whose value is selected or estimated according to the circumstances. Parameters should be distinguished from constants, which are fixed for all uses of the function or model, and variables, which are the actual recorded measurements involved in the function or model.
Many properties of functions and mathematical models can be deduced from their structural characteristics without reference to particular values; such properties include continuity, differentiality, and linear independence. A function or model for a specific purpose may be formulated by first establishing the appropriate structure (e.g. polynomial, differential equation of a certain form) in which particular values are not yet determined; such values are parameters of the function or model. Various techniques can then be used to find the most suitable value or range of values for the parameters when considering the observed set of data.
For simple models, such as elementary probability distributions, parameters may be estimated from the statistics of the sample, such as the mean and the variance. General principles of estimation, in which the criterion is the agreement between model and data, lead to procedures that may require iterative computing to obtain estimates; important examples are the method of least squares and its generalization, the method of maximum likelihood.
The probability distribution of a parameter estimate is often required, and it is usual to compute its standard deviation, known as its standard error (see measures of variation), its correlation with other parameter estimates, and its confidence limits where appropriate (see confidence interval).

Electronics and Electrical Engineering

A quantity that is constant in a given case but has a particular value for each different case considered. Examples include the values of the resistances, capacitances, etc., that form an electrical network or the constants appearing in the equations connecting currents and voltages at the terminals of a network. See also transistor parameters.

Geology and Earth Sciences

In crystallography, the ratio of the intercepts made by a plane (the parametral plane), parallel to a crystal face, which intersects the crystallographic axes, and which has been chosen to define a unit length of intersection along each axis. The form of which the face is a member is called the ‘unit form’, ‘fundamental form’, or ‘parametral form’. See also axial ratio.

Economics

In an economic model, a quantity which is taken as given by an economic agent in their decision-making process. Changes in the outcome in response to a small change in some parameter can be analysed using the comparative statics approach.

单词	parameter
释义	parameter Statistics A constant appearing as part of the description of a probability function or the probability density function of a family of distributions. The shape of the distribution depends on the value(s) given to the parameter(s). For example, the parameters of a binomial distribution are n and p, the parameter of a Poisson distribution is λ, the parameters of a normal distribution are μ and σ, and ν is the parameter of both a chi-squared distribution and a t-distribution. The term is also used more widely; for example it is used to describe the unknowns (α, β) in linear regression and the corresponding terms in the multiple regression model. The word ‘parameter’, in a statistical context, was first used by Sir Ronald Fisher in 1922. Chemical Engineering A variable whose characteristic is not considered and may therefore be taken as being constant. Computer 1. Information passed to a subroutine, procedure, or function. The definition of the procedure is written using formal parameters to denote data items that will be provided when the subroutine is called, and the call of the procedure includes corresponding actual parameters. See also parameter passing. 2. A quantity in a function or mathematical model whose value is selected or estimated according to the circumstances. Parameters should be distinguished from constants, which are fixed for all uses of the function or model, and variables, which are the actual recorded measurements involved in the function or model. Many properties of functions and mathematical models can be deduced from their structural characteristics without reference to particular values; such properties include continuity, differentiality, and linear independence. A function or model for a specific purpose may be formulated by first establishing the appropriate structure (e.g. polynomial, differential equation of a certain form) in which particular values are not yet determined; such values are parameters of the function or model. Various techniques can then be used to find the most suitable value or range of values for the parameters when considering the observed set of data. For simple models, such as elementary probability distributions, parameters may be estimated from the statistics of the sample, such as the mean and the variance. General principles of estimation, in which the criterion is the agreement between model and data, lead to procedures that may require iterative computing to obtain estimates; important examples are the method of least squares and its generalization, the method of maximum likelihood. The probability distribution of a parameter estimate is often required, and it is usual to compute its standard deviation, known as its standard error (see measures of variation), its correlation with other parameter estimates, and its confidence limits where appropriate (see confidence interval). Electronics and Electrical Engineering A quantity that is constant in a given case but has a particular value for each different case considered. Examples include the values of the resistances, capacitances, etc., that form an electrical network or the constants appearing in the equations connecting currents and voltages at the terminals of a network. See also transistor parameters. Geology and Earth Sciences In crystallography, the ratio of the intercepts made by a plane (the parametral plane), parallel to a crystal face, which intersects the crystallographic axes, and which has been chosen to define a unit length of intersection along each axis. The form of which the face is a member is called the ‘unit form’, ‘fundamental form’, or ‘parametral form’. See also axial ratio. Economics In an economic model, a quantity which is taken as given by an economic agent in their decision-making process. Changes in the outcome in response to a small change in some parameter can be analysed using the comparative statics approach.
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