» 普通最小二乘法(OLS)

普通最小二乘法(OLS)

1805
  • Adrien-Marie Legendre
  • Carl Friedrich Gauss
描绘数学统计中普通最小二乘法的办公室历史场景。.

(生成的图像仅供参考)

A standard approach for approximating solutions to overdetermined systems by finding model parameters that minimize the sum of the squared differences between observed and predicted values. This sum is known as the sum of squared residuals (SSR). The goal is to find the parameters [latex]\hat{\beta}[/latex] that minimize the function [latex]S(\beta) = \sum_{i=1}^{n} (y_i – x_i^T \beta)^2[/latex].

方法 of ordinary least squares is a cornerstone of regression analysis. It provides a direct way to estimate the unknown parameters in a linear model. The principle is to find the line (or hyperplane in multiple regression) that is closest to all the data points simultaneously. ‘Closest’ is defined in terms of minimizing the vertical distances from each point to the line, specifically, the sum of the squares of these distances (residuals).

This minimization problem can be solved using calculus. By taking the derivative of the sum of squared residuals function [latex]S(\beta)[/latex] with respect to the parameter vector [latex]\beta[/latex] and setting it to zero, we derive a set of equations known as the ‘normal equations’. In matrix form, these are expressed as [latex]X^T X \hat{\beta} = X^T y[/latex], where [latex]X[/latex] is the matrix of independent variables and [latex]y[/latex] is the vector of the dependent variable.

The solution for the estimated coefficient vector is then given by [latex]\hat{\beta} = (X^T X)^{-1} X^T y[/latex]. This closed-form solution is computationally efficient and provides a unique estimate, provided that the matrix [latex]X^T X[/latex] is invertible (i.e., there is no perfect multicollinearity among the independent variables). Geometrically, the OLS solution corresponds to an orthogonal projection of the outcome vector [latex]y[/latex] onto the vector subspace spanned by the columns of the predictor matrix [latex]X[/latex]. While powerful, OLS is sensitive to outliers, as squaring the residuals gives large errors a disproportionately large influence on the final fit.

UNESCO Nomenclature: 1209
- 统计资料

类型

软件/算法

中断

实质性

使用方法

广泛使用

前体

  • 线性代数(矩阵运算)
  • 微积分(用于寻找最小值)
  • 观测误差理论(由天文学家提出)
  • 解析几何(笛卡尔)

应用

  • 线性回归模型中的参数估计
  • 信号处理 and digital filtering
  • 系统识别的控制理论
  • 用于建模经济关系的计量经济学
  • 天文轨道计算

专利:

NA

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Related to: least squares, OLS, parameter estimation, sum of squared residuals, optimization, normal equations, linear algebra, regression analysis, curve fitting, data fitting.

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历史背景

普通最小二乘法(OLS)

1736
1750
1777
1805
1827
1848
1850
1640
1747
1758
1780
1822
1828
1850
1854

(如果日期未知或不相关,例如“流体力学”,则提供其显著出现的近似估计)

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