Least Squares Estimation in Regression Analysis
Least Squares Estimation is a fundamental method in statistical inference and regression analysis that determines model parameters by minimizing the sum of squared residuals between observed data points and predicted values. This approach relies on linear algebra principles, specifically orthogonal projection onto a subspace defined by design matrix columns, to derive unique coefficient estimates under full rank conditions. It serves as the theoretical foundation for Ordinary Least Squares (OLS) regression within the broader domain of multivariate statistics.
Least Squares Linear Regression as Projection onto the Column Space of X in Machine Learning
Least-squares linear regression assumes the conditional expectation of the response given the inputs is linear in the parameters, and minimizing the squared-error criterion yields the normal-equation…